Why does not the computer processor turn on. What to do if your computer stops loading. Restoring the boot sector of the hard drive

The situation when the computer does not turn on is certainly not pleasant. Sooner or later, this can happen to any PC. But if you want, you can find a way out of any situation, the main thing is not to panic, soberly assess the situation and start acting.

Let's figure out how the problem of not turning on the computer can manifest itself and what the reasons may be and how to find a way out of this situation.

She can show herself in different ways.:

1. When you press the "Start" button, the computer is completely "silent";
2. It started, but it doesn't go beyond the black screen, and a beep is heard;
3. After a seemingly successful turn on, it turns off after a few seconds;
4. Everything seems to work, but only a black screen is visible;
5. At the stage of seemingly successful loading, a blue screen suddenly appears with many incomprehensible codes, and the situation is not corrected.

The reasons for these problems may be:

1. Lack of voltage 220V in the network;
2. Voltage surges;
3. The power button is out of order - Power;
4. Power supply problems;
5. Hardware device problems (faulty, device conflicts);
6. Battery CMOS in BIOS memory has run out;
7. Incorrect BIOS settings;
8. Overheating of the processor and video card;
9. The system board is out of order;
10. Loop problems;
11. Windows crashed or there is a software conflict with device drivers;

Now let's look at each situation in more detail.

The computer is completely silent

When the computer does not react to the power button in any way, and yesterday it was still working, then you need to go from simple to complex. And you need to start with the outlet.

Make sure it's 220V and not 360 or 150, there have already been precedents, so don't laugh.

The computer may not start at a voltage of 210V, it all depends on the quality of the power supply.

There are power supplies (PSUs), where a special switch is provided on the back.

Check if it's enabled.

There are also models where you can switch the input voltage level - 127 and 220 V.

127 V, this is for countries where such a voltage is provided in the network, for example, the USA. These types of devices are typically used by people who frequently change jobs while moving around the world.

If everything is fine and 220 V is suitable for the computer, then the latter will have to be disassembled.

Power button

Button task START - POWER short-circuit the wires leading from the motherboard to each other.

Button view with the front cover removed.

At the end of the wires there is a chip that is put on the contacts. Find these contacts by wire, see.

Check that the chip is tight and well fixed on the contacts.

Take it off and put it back on. If this does not work, carefully close the contacts together with a screwdriver. Do not be afraid, there is no 220V, but the screwdriver must still be with an insulator. God saves man, who save himself.

Watch the video at the end of the article.

If the computer starts, then ring the wires going from the motherboard to the button and if everything is fine with the wires, then change the button.

If you have a tester, you can go an even easier way to test the Power button.

Adjust the tester settings as shown below.

And press the START button - POWER. If everything is normal, then you will hear a characteristic sound from the tester, which means the circuit is closed, if there is no sound, then there is a break somewhere.

Power Supply

If the computer does not turn on, then one of the main reasons for this may be a faulty power supply.

The main sign that the power supply is producing at least some voltage is the glow of the indicator lamp, which is located on the motherboard.

Modern power supplies are connected to the motherboard through 20 - or 24 - pin ATX connectors.

In our case, the connector is 24-pin.

And the plug is 20 - pin - it would be correct to say the ATX connector.

There is nothing wrong with that. It's just that such a plug is connected to the 24-pin connector with an offset to the extreme left position. In this case, 4 contacts remain unused.

When the computer is switched on to the network through the auxiliary converter of the PSU, a voltage of 5 V is supplied to the system board. The indicator lamp on the motherboard "tells us about this"

But it happens that there is no such indicator, so you need to check if at least some voltage reaches the motherboard.

Take a tester and set the settings shown below on it.

Disconnect the ATX connector from the system board and connect power to the computer.

According to the scheme indicated above, we are looking for a voltage of 5 V, which should reach the motherboard.

We also find out if a voltage of 5 V is applied to the PS_ON pin.

Again, using a tester, we check if the voltage is on certain contacts of the ATX connector.

If in at least one of the cases there is no voltage, or it is not significant, then the problem is in the power supply.

If you want to figure it out yourself, then look for the reason in the resistor of the unit itself. It has a resistance of about 1 kΩ and a so-called standby voltage of 5 V passes through it.

Power supply resistors are different. Only an identical brand should be substituted. Some characteristics of the resistors can be seen below.

To avoid any doubts, if possible, install a different power supply on the computer, in 99% of cases this clarifies the situation.

What is PS_ON

PS_ON is a signal that unlocks the start of the main power supply converter to turn on the computer.

When the computer is turned off, as we have already found out above, there is a voltage of five volts at the PS_ON pin.

When you press the START - POWER button, a signal with the same name is sent from the motherboard to the PS_ON contact.

This signal zeroes (0 V) the voltage on the PS_ON pin by shorting it to ground (ground), thereby making it clear to the power supply to turn on the main converters.

The power supply begins to generate current of the specified parameters, supplying it to all computer systems.

If the specified voltage parameters for any reason exceed the permissible ones, for example, as a result of a short circuit, then the main converter stops working and the computer turns off.

It is worth mentioning the PW_OK signal, without which the computer's operation is also impossible. When the computer is off, the voltage at the PW_OK pin is 0.

The power supply receives the PS_ON signal from the motherboard to start the main converters.

At this moment, two voltages of 3 and 5 V are formed in it, which, in turn, begin to progressively form the PW_OK signal having a final voltage of 5 V + - 0.5 V.

Signal formation time from 0.2 to 0.5 seconds. This is the time during which a stable voltage will be formed in the power supply to start the processor and other devices.

After the required voltage indicators have been formed, the PW_OK signal is sent to the contact of the same name and then to the motherboard, where signals are already generated to set the initial parameters of the processor, and then the computer is fully turned on.

The PW_OK signal of 5 volts always exists as long as the PC is running. He kind of tells the system that the voltage is "OK", you can work.

If the voltage in the network drops or rises and the power supply cannot cope with these surges, the PW_OK signal changes its indicators.

Usually the voltage is reduced to 3 or less volts, making it clear to the system that the voltage is not stable, work is not possible.

Then the computer will not be able to start or it will safely shut down due to the fact that the signal to stop the processor arrives before the main voltage disappears.

How important is the PW_OK signal

Unsuccessful first attempt to turn on the computer, what is the reason?

First, let's see how the PW_OK signal can affect freezing and errors when turning on the computer?

What do you think, when the car has a high fuel consumption, when it is just starting to drive or when driving on the highway at the recommended speed?

The answer is obvious, of course at the start.

It also happens when the computer starts up. In the first seconds, the starting current is much higher than that consumed during its further operation.

For example, at startup, the computer can consume up to 300 W, and in operating mode 150 - 200.

At the moment of start, all transistors, capacitors, chokes are switched on, the process of filling the circuit with energy is in progress.

In this situation, the power supply tries to stabilize the voltage as best as possible, to reduce the ripple of currents, which is very large.

If at this moment you send the PW_OK signal to turn on the processor, then it may malfunction, and therefore in memory CMOS BIOS.

For this, there is a delay in the generation of the PW_OK signal (command).

The first sign that this command is formed very early is when the first attempt to turn on the computer fails, and when it is restarted with the Reset button, the boot process is normalized.

You can also use hotkeys Ctrl + Alt + Del.

There are several results:

1. The computer does not have a high-quality PSU;
2. He underlay repair or replacement.

Computer restart

Let's say an attempt to turn on the computer was successful, but after a while it starts to reboot.

What could be the reason?

As we said above, the PW_OK signal is constant when the PC is running. It is equal to 5 V, provided that the standard voltage is in the network, for our country it is 220V.

If the line voltage drops, the PW_OK signal may disappear or decrease. This shuts down the PC before its systems have noticed any network problem.

With the normalization of the voltage in the network, this problem will go away by itself. Therefore, it is recommended to use uninterruptible power supplies for a PC to stabilize the voltage.

Checking the power supply further

In this situation, it is necessary to check whether the voltage is supplied to other PC devices, in addition to the motherboard, through the ATX connector.

Common types of connectors on the power supply, in addition to the ATX connector.

We check the availability of power on the connectors, starting with the most important ones.

On a de-energized computer, disconnect the processor power cord from the system board and connect the tester probes to its connectors.

Connect the PC to the network and press the START - POWER button.

In both cases, the DC voltage must be within 12 V.

If there is no voltage, or it is much less (5, 7V), then you should think about the health of the power supply.

In the same way, we check the power connectors of hard drives, disk drives, etc.

If the voltage is below the standard, then the power supply is clearly faulty.

The computer turns on, but a beep is heard

If you hear that the computer is working, but the system does not boot, and signals are heard, then there is a problem with the hardware devices.

If there are no signals, then check if there is a special speaker on the motherboard.

If not, try to get one and connect it to the Speaker connectors on the motherboard.

There are situations when the speaker burned out, then you just need to replace it.

The signals emitted from the computer can be different. It all depends on the BIOS version that is stitched into the CMOS memory.

It is advisable to have such data at hand, or to spy on them in the documentation for the motherboard.

You can also go to the BIOS with a still working computer and write out its version from there.

Common BIOS versions:

1. Phoenix;
2. Award;
3. Compaq;
4. Dell;
5. Quadtel.

For example, when you turn on the computer, you hear 1 short and 1 long beep. BIOS Award version.

Let's look at the table and see that there is a RAM error.

We open the computer, pay attention to the RAM strips and see.

One bar is not installed correctly.

We fix the error.

The bar is inserted correctly, as a result, the computer starts up without problems.

There are situations when one of the RAM strips is out of order. Revealing it by eye will not work. It is necessary to take out each bar in turn and try to start the PC.

If there is only one bar, then it must be replaced with a similar one. (DDR, DDR2, DDR3, DDR4), do not confuse. It is desirable that all the RAM strips are from the same manufacturer.

Incorrect BIOS settings

BIOS settings are a separate, very extensive topic. If the computer stops booting and a message appears on a black screen, then it just does not appear.

Study it, then the picture will become more, less clear.

A common problem when turning on the computer is the operating system boot source incorrectly set in the BIOS.

There can be several of them: from a hard disk drive (HDD), from a DVD disc, from a USB source and from the network.

Check how these settings are set. If the system, for example, is not installed from scratch, then the first boot source should be HDD.

Often there is such a situation when a USB drive is exposed as the primary source of loading, and a regular, non-bootable, flash drive is inserted into the computer. This may cause an error.

Many PC users do not even know that there is a battery on the motherboard, due to the sparseness of which the computer may not start.

The CMOS memory in which the BIOS resides cannot be non-volatile. A 3-volt battery is provided for its stable operation. It is easy to find on the motherboard.

Its working time is up to 5 years. The first sign that the battery is running low is the constant lag of time on the computer for no reason.

Typically the battery model CR2032, it costs a penny, changes in a few seconds.

But the problem may be different. As a result of a power outage of the CMOS memory in the BIOS, even for a short time, all BIOS settings can be reset.

Therefore, you will have to expose them again. If you don't understand, then just set the factory default settings.

For this, depending on the BIOS version, we are looking for "Load Optimized Defaults" or Load Default Settings. Keywords "Load Defaults".

Overheating of the processor and video card

The importance of the computer cooling system can hardly be overestimated, especially when it comes to cooling the processor, video card, north and south bridges of the motherboard.

The processor is protected from overheating by a special cooler, which you need to know how.

But as a result of improper selection of the latter, its failure or strong dustiness, the processor may overheat.

In order not to burn the CPU, its protection is provided, which turns off the computer when this danger occurs.

Therefore, if you notice that after a few seconds or even minutes after turning on the PC, it turns off by itself, look into the system unit.

Most likely there you will see this picture.

After cleaning the system unit from dust, the situation can be corrected, but not always.

If the situation of self-shutdown of the computer continues, you will have to remove the cooler and get to the processor.

Remove the last one and see the state of the thermal paste.

Over time, it dries up and does not perform the function of improving heat transfer between the CPU and the cooler radiator.

Using rubbing alcohol or cologne, remove the old layer of thermal paste and replace it with a new one.

In the case of a video card, there will be no PC reboot. Most likely you will only see a black screen or hear signals.

If you are sure that the monitor is working properly, remove the video card and clean it from dust.

Remember to remove the old thermal grease and apply a new one. She's there too.

Also, failure of the video card is the reason that the monitor screen is black and the boot process can be seen only at the BIOS boot stage. But we'll talk about the monitor further.

Other devices

We have already briefly touched on the problems with the RAM bars above. All copper contacts of any devices have oxidation properties, especially if the room is humid.

Therefore, they need to be cleaned periodically. To do this, you can use a regular hard eraser.

Also, do not forget about network cards, TV tuner, WI-FI adapter and other devices, if they are in the computer.

If, after cleaning the contacts, the computer still does not turn on, then remember which device was recently installed on the motherboard. Dismantle it.

If this does not help, then go by the method of elimination. Starting with the least significant devices, remove them from their slots and try to turn on the computer. If this does not help, go to the next subsection.

Motherboard

Dust on the motherboard can lead to overheating of the north and south bridges and other microchips.

Therefore, you need to clean your computer from dust at least once every 4-6 months.

The culprit for the failure of the motherboard may also be a poor quality power supply.

Conclusion, you should not save on the power supply.

It is visually difficult to determine that the motherboard is out of order. Although if you look closely, you can find the reason.

Replacing the motherboard can result in a complete upgrade of your computer, and it’s not cheap. It is worth repairing it only when its repair does not exceed 50% of the cost of the new one. But the decision is made by everyone.

Plumes

Loops rarely fail and, as a rule, the problem lies not in them, but in the places where they are connected.

It is especially worth paying attention to the loops: a seven-pin data transfer loop and a fifteen-pin additional voltage loop.

Their disadvantage, weak fastening. Have you transferred the system unit? Hit him with your foot or cleaning equipment? After that, the computer won't boot?

Check the SATA cables for loosening from the hard drive and system board. Disconnect and reconnect them. As a rule, this problem solves.

Blue screen

The theme of the blue screen when loading Windows is very extensive and it is impossible to reveal it in this, and so not a small article.

The problem of this can lie in the plane of both hardware and software failure.

Usually it is solved by dismantling some hardware devices. For example, you have a motherboard from MSI, and a video card from ASUS.

But the incompatibility of devices from different manufacturers, although there is, has recently been extremely rare.

Also, the latest installed drivers can cause the system to crash, etc.

This problem is solved by rolling back the system, through safe boot mode, system restore from a bootable disk or a specially created Windows recovery disk.

But we will definitely talk about this in another article.

Of course, the monitor cannot directly affect the problem with turning on the computer. But when the black screen appeared, it is still worth paying attention to.

An unexpected failure of it can mislead you and against the background of a common problem, there is a high probability that you will take a different path of searching for its causes.

The classic operating voltage of monitors is 12V. If the power supply of the device is external, then it is not difficult to check the output voltage with a tester.

There were cases that the monitor showed signs of its work (LEDs of the connected network), but when the power supply tester checked the power supply, the latter gave out only 7 volts.

As a result, the problem was solved by replacing the monitor power supply unit.

Outcome

We have considered the main reasons why the computer refuses to turn on and the operating system to boot.

You need to understand that the main problem is not how to eliminate them, but how to identify them.

The computer won't boot! What to do?

Unfortunately, the computer does not always make us happy with excellent and smooth operation.

It is quite possible that the computer will "refuse" to boot, and then a completely natural question arises - what is the reason for the failure and how to fix it? It is impossible to clearly define the list of reasons why a computer may stop booting. There are a great many of these reasons and you need to understand each specific situation separately. But you can still significantly narrow down the search for the cause of the failure, if you determine at what stage of the computer bootup it occurs.

After you press the button to turn on the computer, several scenarios are possible:

1. The computer will emit a series of beeps and either shutdown or restart, or display a black screen with various text information. In the latter case, as a rule, it will be possible to continue loading after pressing the F1 key.
2. A black screen will appear with only one inscription and the computer can only be rebooted or turned off.
3. A blue screen with text appears.
4. Ideally, the entire boot process will go through and you will see your desktop.

Booting a computer consists of several steps, and in order to understand at which step the problem arose, you should understand the whole process in general terms. The above options for the development of events are tied precisely to certain steps of computer boot and let's get to know it in more detail.

So, you pressed the Power button (turning on the computer). Immediately after switching on, control of the computer is transferred. BIOS using the on-board POST program (eng. Power-On Self-Test- self-test after switching on), checks the operation of all computer devices. If during testing non-working devices are found or problems are identified in their operation, you will hear a series of beeps.

There are several BIOS manufacturers, so it is impossible to say for sure what the sequence of long and short signals will mean in your case. The best recommendation in this case is to find a manual from your computer's motherboard. There will definitely be a section on BIOS signals. This information is usually sufficient to identify the device causing the problem.

You can also find a list of beeps from various BIOS manufacturers on the WikiPedia website.

If there is a breakdown or a failure is not critical for the operation of the computer, then the POST program will display a message about the problem at the bottom of the screen and, after reviewing it, you can continue loading by pressing the F1 key.

List of the most common mistakes

Here are the most common error messages.

Error message

• CMOS battery failed
• CMOS Battery Has Failed
• CMOSBatteryState Low
• State Battery CMOS Low
• CMOS Battery Low
• System battery is dead

Possible reasons

The battery supplying the BIOS chip is defective. Most likely, it is discharged and should be replaced.

Error messages

• DISK BOOT FAILURE
• INSERT SYSTEM DISK AND PRESS ENTER
• HARD DISK INSTALL FAILURE

Possible reasons

No boot disk found. You need to check if the hard disk is connected properly. Pay attention both to the connection of the ribbon cable (wire) to the disk itself, and to the connector for connecting the ribbon cable to the motherboard. Also pay attention to the power supply - the power cable from the power supply must be connected to the hard disk.

If everything is connected correctly, then try booting from another device, for example, from a USB flash drive. To do this, you must first create a bootable USB flash drive.

Also, this message may appear when you try to boot the computer from a new hard drive that does not yet have boot files (operating system). In this case, you need to install the operating system on the disk using the disk with the distribution kit (installation files).

Error messages

• Memory Address Error at XXXX
• Memory test fail
• Memory Verify Error at XXXX

Possible reasons

All error messages that include the word "Memory" refer to RAM and indicate errors during testing. If these errors are repeated when the computer boots, then the RAM module should be replaced. If you have two modules installed, you should remove one module. If the computer works normally, then after a while it is worth replacing the memory module in the computer with the one removed earlier and working for some more time. Thus, you can identify which of the modules is damaged.

Error messages

• K / B Interface Error
• Keyboard / Interface Error
• Keyboard Error, press F1 to continue
• Keyboard failure, press F1 to continue

Possible reasons

If the message contains the word "Keyboard", then we are talking about a communication error with the keyboard. Check if the keyboard is properly connected to the computer. If everything is connected correctly, replace the keyboard to test.

Error messages

• Diskette drive A / B error
• Incorrect Drive A / B - run SETUP
• Floppy disk (s) fail
• Floppy disk (s) fail (40)

Possible reasons

If the message includes the words "drive A" or "Floppy disk", then we are talking about already obsolete floppy drives. You need to go to BIOS and check the settings in the Standart CMOS section.

You need to find the item Drive A or Floppy - 1.44 and set the value None or Disable opposite it.

Error messages

• ERROR: CPU FAN Error
• Fan error

Possible reasons

This error usually appears on not very new computers and laptops and is associated with malfunctions in the processor cooling system. Usually, after such a warning, you can continue to boot the computer, but in any case, you should find out the cause of its occurrence.

I have come across two situations in which this error occurs:

1. Due to wear and tear on the fan, it will not start on its own. We need to replace it.
2. Something is preventing the fan from starting. In my case, a plastic holder broke off inside the laptop and hit the fan. The problem was solved after removing it from the fan.

If in this list you did not see the message that appears in your case and it is not clear from the message itself which device is in question, then you should. To do this, just type a message in the search field of Yandex or Google.

If the computer does not boot and gives sound warnings, then I recommend turning off the computer, removing the cover of the system unit and carefully checking all the devices inside the computer. It is quite possible that some of the devices were poorly fixed and a little "jumped out" of the connector (slot). I came across a similar situation when the video card was not attached to the computer with a screw and when the monitor was connected to it, it slightly "jumped" out of the connector. Therefore, first of all, check the reliability of fastening the devices and if everything is in order, then pay attention to exactly the device to which you were indicated by the sound signal or the message on the screen.

The “suspicious” device should be replaced with a similar one to check its functionality and then you either replace / repair the device under warranty, or purchase a new one.

Q
QUESTIONS:

The computer turns on but DOES NOT BOOT!
only black screen ... What to do? ...

Where to start troubleshooting if your computer won't boot BIOS POST?
There is not even a sound signal, but the power supply is working, the fans are spinning ...

A
ANSWER:

If the computer turns on, but DOES NOT BOOT (DO NOT START), then there can be quite a few reasons.

Sometimes inexperienced people describe this situation like this: "... the computer boots up, the fans are spinning, but the screen is black." - as if for a computer the rotation of the fans is more important than anything else ...

PRIMARILY you need to pay attention -
can you hear at the start one short squeak from the system unit?
Or this squeak not one, but several.
Then what exactly are these squeaks (for example, 3 short + 1 long, or in some other sequence) - these are the motherboard error codes that should be output at the start BIOS POST (Power-On-Self-Test \u003d power-on self-test).

One short squeak is a message that everything OK.
And if there is no squeak at all, or vice versa, if they are several different in duration or one long - this indicates that there are some malfunctions.
There are special guides (for example, "wikipedia.org - BIOS beeps") describing which malfunction certain sound sequences correspond to. Some of the more important options from this list, specific to your motherboard, can be found in manual (user instructions).

If you have heard a certain sequence of sounds, then usually according to the description you can immediately understand (unfortunately, not always with great accuracy) which of the devices connected to the "motherboard" is to blame for the problem.

If there are no sounds, or the guide did not help,
then the sequence of actions is as follows:

We will act according to the principle of a comic saying:
"Electronics is the science of contacts!"

As you can imagine, this joke contains (only) a grain of joke ...

1. Open the system unit.
It is enough to remove left side coverif you look "From the face".
That is, it is convenient to put the system unit on the right side
and remove the cover that turned out to be from above.

Let's see if there is a lot of dust in the case and on the motherboard.
First, clean slightly with a vacuum cleaner. A paintbrush from a hardware store that is used to paint windows helps a lot - choose a flat, rather than a round brush with the longest bristle. We sweep with a brush, especially in the gaps of the radiator grilles, and suck with a vacuum cleaner (in the other hand).

Be careful! Do not break any parts soldered to the motherboard with the brush or the bell of the vacuum cleaner!

If you unscrew the fans from the case and from the processor cooler, then the picture can be depressing:

Cooler (from english COOLER \u003d cooler) is a radiator (such an aluminum or copper lattice "brick") with a fan installed on it.

What kind of cooling is there if the cooler's radiator is dullly clogged with a dust coat?

This is what a new or cleaned up standard CPU cooler looks like (somewhat outdated):

And here are the options for modern more advanced models:

2. Next, you need to snap out (remove) / click (insert) the RAM modules. To do this, notice the plastic (usually black) levers at the ends of the module. If you bend these levers to the sides with a little effort, the RAM module "jumps out" of the slot by itself.
When removed, we clean the knife contact with the same brush (the slot where the modules are inserted).
On the modules themselves, see the state of the gold-plated contacts -
whether everything is in place, whether some one is dirty.
It does not interfere with gently wiping with a soft cloth dipped in alcohol.
Vodka will do too - just not a cologne !!!

You need to insert the module into the slot very neat... Insert the knife contacts into the slot, it is possible under a slight slope, as it turns out. And then lightly press your fingers first on the edge of the module, which was higher, then on the other edge, so that the module snaps into the slot. In this case, the levers at the edges of the module will themselves stand upright.

If the video card has a cooler (a heatsink with a fan), check its condition.
You can use a small screwdriver to unscrew the fan and clean it from dust along with the radiator.

If the cooler is noisy, you can drop a little machine oil into its bearing (at least from a sewing machine) - for this, temporarily remove the sticker that covers the bearing.
Oil should be VERY LITTLE - do not overdo it !!!
Dip a small screwdriver in oil and transfer to the bearing LITTLE DROP with this screwdriver. Then spin the fan while gently pushing the blades with your finger to spread the oil through the bearing.

After that, you can try to "start".

4. If it does not start, disconnect all hard drives, optical drives and other peripherals from the "motherboard".

We leave ONLY FUNCTIONAL MEMORY, CPU and VIDEO CARD.
Remember to disconnect the wires USBleading from the motherboard to the front of the case (to the USB connector or a card reader built into the front panel, if any) - because of them, there is often a problem, such as yours.

5. Trying to "start".
If it does not start in this position, set to zero. BIOS
(Basic Input-Output System \u003d basic I / O system)

This is done by permutation jumper (from English JUMPER \u003d jumper), i.e. jumper, usually located near the battery (see photo below). It says something like "Clear RTC" (erase real time \u003d REAL TIME CLOCK) or "Clear CMOS".

For reference:

CMOS = Complementary-symmetry / metal-oxide semiconductor - technology for constructing semiconductor electronic boards.
This abbreviation is purely historical - once BIOS CMOS was the only microcircuit on the motherboard ( SYSTEM BOARD \u003d SYSTEM BOARD WITH CONNECTORS)

Usually a group of 3 contacts is intended for installing a jumper on the board. The jumper is installed so that the middle and one of the extreme ones are closed. Repositioning to the position where it closes the middle and OTHER EXTREME resets BIOS settings to default (from English DEFAULT \u003d default).

One of these three contacts is usually signed - look for a white number near it 1 or some kind of icon in the form of a small arrow (or just a wide white strip, as in the photo below). And next to it there is a small sign on which something like
(may differ exactly the opposite):

1-2 NORMAL
2-3 CLEAR CMOS (RTC)

This means that in position 2-3 custom settings will be erased BIOS.
Move the jumper to position CLEAR CMOS and wait 10-15 seconds.
Thereafter DO NOT FORGET return to position NORMAL.

If you have not found such a jumper, remove the battery for 30 seconds and insert it back.
On company boards Gigabyte there is no jumper, but this is exactly what the manual (user manual) says:

I am translating the explanatory text for this manual:

BATTERY:

If you want to erase CMOS values

1. Turn off your computer and unplug the power cord from the outlet
2. Remove the battery and wait 30 seconds (highlighted in the picture)
3. Reinstall the battery
4. Connect the power cable and start the computer

[It is written to the right:]

WARNING:

RISK OF EXPLOSION if battery is incorrectly replaced
- Replace only with the same model recommended by the manufacturer
- Dispose (throw away) used batteries only in accordance with the manufacturer's recommendations

When taking out the battery, be VERY CAREFUL !!!

There have been cases when inaccurate handling caused BATTERY BREAK -
very unpleasant "VESCH", I will report to you!
(there is a warning about this in the manual above)

This, of course, is not an explosion (as it is written there), but ...
a small (Thank God!) amount of CORROSIVE ALKALI!
Which, as you know, immediately corrodes any clothing and is very
NOT USEFUL FOR EYES, EARS, NOZZLES and COMPUTER PARTS !!!

Please note that all this must be done
ON A FULLY DE-ENERGIZED MOTHER BOARD !!!
(That is, it is necessary, as it is written in the manual, to disconnect the power cable from the outlet!)

Some motherboards have a special indicator light, which just by its glow reminds that it is necessary to de-energize the board before turning on or off something on it.
For example, look at the photos above - at the bottom left there is such a green light.

6. If it does not start now, check how the processor is installed, the memory itself, etc.
This is already, as they say - "AEROBATICS", so with no experience, don't poke your nose!

However, disassembly cpu cooling systems and replacing the thermal paste, which may have already dried up and instead of accelerating the removal of excess heat, works like a "fur coat", is not so difficult - read the step-by-step description of the procedure in the topic about laptops:

Waking up in the morning, with the usual push of a button, you turn on your PC, and ... nothing happens. You can panic, or start calling all your acquaintances who "seem to be a programmer or a designer ... But you have to understand computers!", Or you can try to figure out what's the matter yourself. Possible reasons why the computer does not turn on and what to do about it, we will try to consider in this article.

An important amendment: we will consider situations only when the computer does not turn on at all

1. after pressing the "Power" button, nothing happens at all
2. the computer tries to boot (the lights come on, the fan starts working), but shuts down immediately
3. the bulbs are working, a squeak is heard, but the computer does not boot.

Computer does not start - looking for the reason

The very first and seemingly trivial step is to check the network connection and the operation of the cables. The advice may seem silly to someone, but in fact, at this stage, sometimes up to half of the situations are cut off. It is worth checking if the cable has come off, the outlet is working.

These tips universally apply to other related devices: mice, printers, speakers, keyboards.

Checking the cable is just pulling it out and it's better to plug it into the socket. If the wire looks poor-quality and weak, of course it is worth trying a new one for the sake of checking - at least for the cable from the monitor. And be sure to make sure that the button on the power supply (usually located near the power connector) is in the correct position.

The main thing is not to confuse it with the input voltage switch button.

It is necessary to change the input voltage level between the American 127 V standard and our 220-volt one.

It is important that the outlet is powered by 220 volts - the functionality of the outlet is easily checked by connecting other devices. If many consumers are connected to a single power source through T-pieces, the load may be exceeded.

In such a situation, it is advisable to disconnect the other devices and check if the PC turns on if it is connected alone.

If the voltage exceeds or, on the contrary, does not reach the required rate, the machine may burn out or simply not turn on. There are special devices for testing voltage, but you can determine the level without them, if there is an ordinary light bulb... If the voltage is insufficient, the light will shine weakly. If the voltage is too high, then the opposite situation is observed, the light bulb shines brightly, after which it can burn out.

If the computer beeps and does not turn on, we can try to determine the cause of the failure by the sound.

It is advisable to once again make sure that the speaker is correctly connected to the motherboard - perhaps the computer wants to give you a signal, but you do not suspect.

This problem is especially relevant for users who have never heard such squeaks from their own PC before.

Problems on each BIOS version may sound differently. They can be higher or lower, longer or shorter, the combinations of signals may also not coincide. Let's consider some options.

For instance, on one of the BIOS versions you can hear the following options:

• triple long / triple long - single short: motherboard problems.
• Double short: PC does not see the monitor.
• Short with repetitions / long without stopping: power supply failure, or motherboard malfunction.

In another version of BIOS signaling can be as follows:

• Triple long: problems with the input device controller.
• Long-term without stopping: power supply failure.
• Single long - double short: video adapter not detected or disabled
• Long or short signals with constant repetitions: the RAM module is not detected or is disabled.

In the third considered version of BIOS there is an important feature. Here the signals are built on a system using several beep sequences. Older versions will have three sequences and newer versions will have four.

• Long signal with constant repetitions: motherboard malfunction.
• Long non-stop: broken or off fan.
• Single - Single - Double: CPU failure, replacement is desirable.
• Triple - triple - quadruple: video adapter memory not initialized
• Triple - quadruple - single: the computer does not see the monitor, or else fixes its error.
• Triple - Double - Quadruple: No input controller initialization.

Consider another version of BIOS, the signals in which will sound as follows:

• Sevenfold short: the motherboard is broken
• Five-fold short: PC has detected a CPU malfunction
• Single long - four times short: the video adapter is not detected, or its error is noted.

In order to decipher what your computer is beeping about, you should know from which manufacturer of your motherboard's BIOS.

A general list of possible problems:

1. system voltage problems
2. the motherboard battery is dead
3. power button malfunction
4. connection or parts problems

If there is a fault in the power supply

Perhaps the most unpleasant problem can befall your PC if the power supply itself is broken or burned out. Unsurprisingly, then, the computer refuses to turn on. Moreover, such an event may cause damage to other connected components.

You can check the existing power supply using a voltmeter, and for deeper diagnostics, you will also need an ohmmeter.

But this method is only suitable for situations when the computer does not boot, and the lights are on. To check, the power connector is taken and the voltage is measured on it. This indicator between the red and black conductors should be 5 volts, between the black and yellow wires - 12 volts.

You can try to fix the problem by unplugging the power cord so that the computer remains unplugged for a while. Then return the cable back and make a test run of the computer. There are situations when after long use, from wear and tear, the effect of "sticking" is created in the inner protection. If this did not help and still failed to start the computer, proceed to the next steps.

Yes, oddly enough, ordinary dust and dirt inside the computer can greatly affect its operation and be one of the reasons why the computer does not turn on... In order to test this hypothesis, you will need to clean the insides of the system unit (and the components would not hurt), it will not be superfluous anyway.

Cleaning should be done with a mini-vacuum cleaner and a brush, preferably not with cotton wool or paper discs, so that particles of fibers do not remain inside.

The suggested order is as follows:

• We clean the contacts of the RAM and boards.

To do this, the computer is disconnected from the network, the memory is removed. Many experts say that contacts can be cleaned with a regular eraser, someone uses a cotton rag the old fashioned way.
Attention: do not wipe the entire memory strip, but only the contact track!

This is required in order to remove the existing oxidation, which can interrupt the contact between the RAM and the motherboard. After that, you can walk with a brush, or a brush with soft bristles, so as not to damage the microscopic parts.

• We do the same with other cards, such as a video card.
• Checking the processor coolers for contamination.

We clean, see if the fans are spinning. Due to contamination of the fans, the cooling system may not work well, in which case the computer will overheat and unexpectedly restart itself.

Inoperative battery

All motherboards have a small coin cell battery. It is often called a "battery for BIOS", as it supports CMOS memory, which, in turn, stores PC configuration parameters (BIOS Setup settings), as well as the system timer. Motherboards use lithium batteries that differ in capacity and thickness. On average, their service life is 2-5 years, so if the computer has been in use for such a period, or even has been in a warehouse, the battery runs out. And with it the settings are lost.

Often times, PC owners discover this because time settings are lost every time (as we indicated above, the battery maintains a store of system timer settings).

Sometimes problems with the battery are detected in other ways, through system messages, failure to launch some programs, even problems with working inside the browser. But up to the fact that the computer does not turn on, or turns on every other time.

The easiest way to check if the battery is the case is to buy a new one. They are not expensive, within 50-100 rubles. If you can't buy a battery of the required type yet, but you have a voltage tester (voltmeter, multimeter) at hand, you can check the voltage. 2.7 - 3V - normal voltage for CMOS BIOS operation.

It happens when a joyful user comes home, presses the power button of his faithful companion, but he is silent. The computer just won't turn on. A person begins to panic and call friends who understand at least something in computers, and those, in a stupor from such a direct question, without explaining the reasons and features, do not even know what to answer. And okay, if the technique was included to launch the game, but if its launch was necessary for operational purposes?

The computer simply cannot turn off and that's it. There is a reason for this, and more than one, so it is impossible to determine it without describing the features. But if you take a closer look at the signs of breakdown, then everything can be eliminated without difficulty. Such situations arise for a variety of reasons. Some of them, at the end of the problem, will only cause hysterical laughter, while others will empty the wallet.

Lack of electricity

It happens when a person just comes to the apartment, or just wakes up and immediately turns on the computer. And he, the infection, does not turn on. Thinking about the reason for such a tragedy takes a lot of time, but in fact, there may simply not be electricity (after all, the TV, light and other devices did not turn on at that time).
It's all easy to check, and you shouldn't go online for advice in such situations. But it may also be such that all equipment turns on, but the computer does not. There is a chance that the power supply is not available at a specific outlet.

Electricians know why this happens, but you can check it yourself by plugging in a hairdryer or other equipment. If it doesn't work, then the reason is in the outlet. The power supply must be brought to another source, and the outlet itself must not be touched until the master arrives. If the reason is not in the outlet, then go ahead.

Computer power

It may be that everything is fine with the outlet, but the power still does not reach the computer. First you need to check the integrity of the cable, and carry out a simple manipulation: remove it and insert it. If by the appearance of the cord it is clear that it is time for it to go to the trash heap, then it is better to do so by buying a new one. Even if the reason for the bad start of the PC is not in it.
Also, there is a special button behind the system unit. It is rarely used, but accidentally hook it, and then wonder why the computer does not work quite realistically. It needs to be switched to the "On" position.

Power Supply

If there is no problem in the outlet and cord, but the problem remains, then you need to follow the electricity. After the cable, it goes to the power supply, where the path is for us. People are accustomed to saving on everything they can. In computers, power supplies are at the forefront of saving plans. People don't fully understand how important this technical detail is.

If it breaks down and needs to be replaced with a new one, it is still not scary and will cost 35-50 dollars. Problems will be more serious if not only the power supply unit breaks down, but also other parts like the motherboard or video card.

It is also not worth buying new parts right away, first you need to check everything. The easiest way to do this is if you have another, serviceable power supply unit. If this is not the case, then you need a voltage tester. The power connectors should have a voltage of 5V between the black and red wires, and 12V between the yellow and black wires. The deviation is possible only within 5-7 percent, if more, then the block urgently needs to be changed. So that in the future there are no problems with the inoperability of other elements of the system unit, it must be replaced, and not repaired.

When the power supply unit becomes faulty, the internal protection may "stick". You need to unplug the power cable for a few minutes and leave the PC unplugged. If after that, it still does not start, the reason must be looked for in another.

My battery is almost done

There is a small 3V lithium battery on the surface of the motherboard. It supports the memory system in which the BIOS settings are stored. It is very difficult to check this battery before buying a computer, because in order to see it, you need to disassemble the computer. And it is quite difficult to check the performance in appearance. And it may well turn out to be used. Or it could have been in the warehouse for several years.

When the battery runs out, the BIOS settings are reset. A permanent failure of time can become a symptom of such a malfunction. Also, in case of problems with the battery, when you turn on the computer, it will require you to save the BIOS settings. In some cases, the technique generally refuses to turn on. You also need to check its performance using a tester. If it turns out to be inoperative, or there is simply no tester at hand, then you can replace it. These batteries are sold in every computer store and are inexpensive.

Checking the processor and hard drive

If the cover of the system unit was removed to check the power supply and the battery, then at the same time you can look at the processor and hard drive. To find out if the processor is working, you need to remove the cooler from it, start the computer and put your hand on the radiator. If it starts to heat up, it means that it is working. But it's also worth seeing if the cooler is working. If not, the computer will shut down to avoid overheating, and it does not always start.

The hard drive can also be a startup problem. You need to check if all plugs are tightly connected to it.

Dust in the computer

If there is a lot of dust inside the system unit, it is not strange that the computer does not start. To fix the problem, you need a regular vacuum cleaner. The entire cleaning process consists of several stages:

Viruses

The reason why the computer does not turn on may be a virus. They become real computer killers, viruses can do harm in a variety of situations. If a person uses the Internet, and he has a bad antivirus installed, or not installed at all, then viruses will quickly come from the World Wide Web to the computer. The best pest control method is a quality antivirus. It must be official and must be updated periodically. There is no need to save on this software.

But there are situations when the PC turns on, but the operating system does not. How do you run the antivirus in this case? You should try loading the last known good configuration. To do this, when you turn on the computer, press F8. After pressing the key, a menu will appear on the screen in which you need to select "Load the last good configuration".

If you cannot start a successful configuration, then you should try to enter safe mode. To do this, you should also use F8. When you press the key, a special menu appears on the screen, in which you need to select the "Safe Mode" line. If you managed to start the OS, then you need to proceed as follows:

• Go to the "Start" menu;
• Select the "All Programs" menu;
• Select "Standard";
• Open the "Service" window;
• Click on "System Restore";

BIOS settings

Most users don't even know what this BIOS is. In fact, there is no need to get involved in this issue, it is better to immediately fix the problem. If the computer does not turn on due to incorrect BIOS settings, then you need to remove them, reset or return them to the factory settings. You can call this process whatever you like. If the PC still turns on, but only sometimes, then you need to go to BIOS when the system starts. In order to enter it, you need to press the Del or F2 key (depending on each computer). Next, in the menu that opens (in blue), click on Load Optimized Files. If the computer does not turn on at all, then you need to reset the BIOS in another way.

First you need to remove the cover of the system unit and find the motherboard inside. On its surface there is a “Clear CMOS” jumper, which is what we need. It needs to be "settled" in neighboring contacts, or simply removed for a few minutes. After that, put back and start the computer.

Motherboard

If the settings are reset, the computer is dust-free and everything is in order with the power supply, but the equipment still does not turn on, then the worst case is possible. If the motherboard is broken, then it will fly into a lump sum. Especially if there is a desire to take a modern motherboard, which will lead to the purchase of a new processor, RAM and video card. As a result, almost the entire computer will have to be updated. Well, it had to be done sometime.
The process of replacing a motherboard is not easy; when replacing, you need to consider the following factors:

• The new board must have the same socket for the processor;
• You need to check the number of RAM slots, they must be of the same type (DDR, DDR2, DDR3, etc.);
• The hard drive connection should be the same;
• The required number of slots for the required boards;

If all this is not taken into account, then a new problem will arise. Now the user will be tormented by the question why the new motherboard does not start. Also, new hardware may have different system settings, and you will have to reinstall the operating system.

The logical question will be why not hand over the motherboard for repair? This can only be done if the cost of repair services does not exceed 30% of the price of the whole fee. Repairing this part of the computer is a very difficult process and there is no guarantee that it will work well in the future.

If all possible methods of solving the problem have been used, and the technique does not turn on further, then you should not be upset. You need to call a wizard who will determine the cause of the malfunction and eliminate it.