The power button on the computer does not work
What to do if the computer does not turn on after you press the power button??
A fairly common problem is the lack of response to clicking the power button on the computer. In other words when you try to turn the computer on as usual by pressing a button nothing happens. This article will describe possible causes of this behavior.
So let’s begin. Here is a list of possible causes:
- No voltage in the electrical outlet;
- A damaged or loose contact between the power cord going from the socket to the computer power supply;
- Power button is in the off position;
- Breakage of the power button of the computer or its wires;
- Failure of the power supply;
- Motherboard failure.
The first thing to start diagnosing this problem is to make sure that there is voltage in the electrical outlet. You don’t have to do it with a tester. It is enough to plug in some other electrical device and make sure that it works.
Next, you need to check whether the black power cord is securely connected to the electrical outlet and power supply unit, as well as to make its external inspection for damage and fractures, especially at the ends of both connectors. To do this pull its end out of the power supply of the computer and insert it back in.
The next step is to pay attention to the power supply of the computer. To do this, look at the back of the system unit in the place where the power cable comes from the outlet.
If there is a button. switch, it should be in the switched on state.
After that you should try to start the computer without the power button.
Check the power button for proper operation
If the first actions to identify possible causes have not yielded results, then proceed to testing the serviceability of the computer power button. But how do you check it?? To do this, also turn off the computer power and open the system unit, unscrewing and removing its left side cover. Next, at the bottom of the motherboard we find the connector block from the front panel of the case. We are interested in the POWER SW connector. Disconnect it and use the multimeter to check if the button works.
This is done simply by inserting the stylus of the multimeter into the holes of the disconnected connector, and pre-setting the device in the test mode, press the power button on the computer. If the device squeaks when you press it, it means that the button works and the wires to the motherboard are intact.
Pay attention: when in the testing mode observe the polarity of the probes does not matter. It does not matter which probe you insert and into which hole of the plug.
If you do not have such a device, you can try to turn on the computer without the power button, using the most common household tool. a screwdriver. In this case also disconnect the POWER SW socket and give power to the system unit. Then using the flat side of the screwdriver close the two pins of the POWER SW connector on the motherboard, thus simulating the closure of the power button contacts. If the motherboard and the computer as a whole can be started, then the reason is in the button, if you can not turn on the motherboard, then continue to search for the causes of failure.
Checking the power supply
The next step in determining the possible reason why the computer does not turn on by pressing the power button is to check the health of its power supply unit. The following method is not a 100% guarantee of its serviceability, but only allows you to make a superficial diagnosis.
As before, open the system unit, pre-disconnect it, and disconnect from all devices and the motherboard connectors power supply. Next, take the connector ATX, it can be 20-t or 24-pin, it all depends on the model of power supply, and short the green and any black contact on it jumper.
After that connect the PSU to the mains. If it has a working fan, it is more than possible to say that PSU works. For a more detailed check of its working order it is necessary to check the output voltages. 5V and 12V.
First of all let’s check if the output voltage is 5V. Using multimeter we set the mode of measuring DC voltage and put the feelers into the holes of ATX connector. COM and 5V. When measuring do not forget to observe their polarity. Connect the black dipstick to COM, the red dipstick to 5V.
Next step is to check if 5V is present at PS_ON. Again we take the probe and put the red one on PS_ON, the black one on COM.
And by analogy, let’s check if the PSU produces 12V voltage at the ATX socket and a 4 pin connector, which feeds the line for the trimmer of the processor. Again, respecting the polarity, insert the red probe of the device into the contact with the yellow wire, and the black into the contact with the black wire.
At the end of the PSU surface diagnostics you can check if there are no blown capacitors on its board, which can also be the reason of PSU failure, and as a result the computer does not start after the ON button. If they are found, they should be replaced.
If all the made measurements did not reveal irregularities in the work of the power supply unit then it is most likely to be in good order. It remains only to rely on reset BIOS settings. If this does not help, you will need expert help from any of the service centers for computer repair.
Reasons why the computer does not turn on
Faulty power supply
This is one of the most common reasons why the computer does not turn on. Power supply is responsible for converting and supplying electricity to all computer components. It has a fuse that protects the computer from overvoltage. Sometimes it burns out, and by replacing it or the whole power supply, you can continue to work.
Also, PSU may fail for many other reasons, for example, the fan that cools it down is clogged with dust and can no longer properly reduce the temperature. The components overheat and the wiring melts. Often people complain that the system unit is smoking or that there was a sharp smell of burnt wires. believe me this is the case.
Check that the computer does not turn on because of a faulty power supply is very simple. Enough to hook up for a while another power supply to all the components of the PC, turn it into a socket and press the power button. If the PC turned on and worked normally. go to the store for a new PSU.
Here all is clear. The computer may not turn on because there is no electricity at home. How to check if it is there I think you know. Also, don’t forget to press the button on the surge protector to the “ON” position (the button should light up).
Also, on the back of the case of the system unit, where all the connectors are, there should be a switch on the power supply. It looks similar to the one on the surge protector. It should also be in the “ON” position
You need to clean the dust
Dust is a good conductor of electricity. If it is lying in large piles on the hardware of your PC, then it is not surprising why it does not turn on.
In this situation you need to disassemble the system unit, clean it from dust, replace the thermal paste where necessary, and if necessary, grease the fans. If you have cleaned the computer but it still does not turn on.
You need to reset the BIOS
The computer does not turn on because you need to reset the BIOS. This problem is less frequent than the ones I mentioned above. Resetting the BIOS is easy. You need to find the motherboard slot, in which the battery is inserted and remove the battery for 20-30 seconds, pre-disconnect the system unit from the mains.
Usually enough time for the system settings to reset. Now put the battery back in and try to power your PC.
The power button is defective.
Maybe the computer does not turn on because the power button itself does not work. I have had about 8 such cases in my life. To check this problem is simple enough. First, you need to power off the system unit. Then, find the POWER SW wire (it can also be called PWR SW), pull it out and the 2 pins that are free, short-circuit it with something, like a screwdriver.
If the PC turned on, you might have a broken wire somewhere. I usually do not bother and if the customer had a reset button on the front panel, (this wire is already called RESET SW or RST SW) then, if he agrees I just put the reset wire in place of the power cord and the reset button became the power button.
Requires all connectors and loops to be tucked in
Rarely has the power cord been at fault. To check it is also quite simple. You need to pull it out of the socket and out of the system unit and examine it for kinks, cracks, and other defects. Many monitors use the same cable as the system unit, so you can take the cable out of the monitor and plug it into the system unit. Then press the power button.
If it works with the monitor from the system unit I suggest you tweak all PC wires and open the lid of the system unit and tweak all connectors. In my practice I had a case when after moving the PC did not turn on. It appears that the power to the motherboard is a little loose. (The cable’s special clasp was broken).
The motherboard is broken
The motherboard is faulty. the most complicated variant. The breakage requires its replacement. Sometimes it is a good idea to buy a new PC. If you change the motherboard, you need to consider the following factors:
- The board with the same socket as the old one.
- The RAM must have the same number of slots of the same type (DDR, DDR2, DDR3).
- The same interface of the hard disk (SATA or IDE).
- The graphics card connector must match (PCI-E or AGP).
If all of the above tips you have tried, but the computer still does not turn on, then you probably have a hardware problem. Finding the cause (a broken component) is fairly quick and easy, but only if you have test parts. By pulling components one by one and replacing them with known working components you will quickly find out the cause of which your computer does not turn on.
Check the motherboard
Assuming that the power supply has passed the start test by shorting the contacts and no blown capacitors have been found inside the power supply. Ideally, if you have at hand another known working unit, which you connected to the motherboard to test, but when you press the power button, still nothing happens.
The conclusion is that the motherboard is faulty, but we can not exclude the possibility that the power button does not work.
Locate the front panel connectors at the bottom of the motherboard which hold the power and reset button, and also the LEDs on the chassis. As a rule, the pins are signed:
- Power LED. Power Signal (LED)
- HDD LED. hard disk drive work signal (LED)
- Power Switch. Power button
- Reser Switsh. reset button
We are interested in the pins of the power button, which, depending on the company of the board manufacturer can be labeled PWR BIN, PWR SW, ON/OF, PW_ON, PW, etc.д.
Disconnect the wires from the POWER SW pins and short the pins with a paper clip or jumper. This is tantamount to pressing the power button.
If the fans start spinning, then the problem is in the button, maybe there is a loose contact. But if by shorting the corresponding pins nothing happens, then you have a faulty motherboard.
At this point the diagnostics is over and you will need the help of a specialist. The only thing you can try is to reset BIOS, but I don’t remember it working in this situation.
The computer does not turn on from the power button. what to do
Yesterday the computer was working fine, but today when you press the power button it does not show any signs of life. What can be the problem? Is it possible to fix it yourself or can not do without the help of a wizard? Let’s look into it.
As practice shows, in most cases the power button on the system unit “Power” stops starting the computer for the following reasons:
- Lack of voltage in the 220 V mains;
- Failure of AC filter or uninterruptible power supply unit, through which PC receives power;
- The power cord is damaged or there is no contact at the connection points;
- malfunction of the power supply unit (PSU);
- Lack of contact in the socket, through which the PSU is connected to the motherboard;
- The BIOS memory battery has failed (no charge);
- The “Start” button on the system unit is jammed or has failed;
- The system unit button does not work because it is blocked by static electricity.
If the computer does not respond when you press the Power button, the first thing to start with is to check if the system unit is securely connected to the network.
- Make sure that the power supply button (on the back of the system unit) is in the “ON” position.
- For a while try to connect the computer to the outlet directly, without a surge protector.
- Verify that the outlet itself works by plugging in any other working electrical appliance.
- Next, check the power cord for damage (especially if you have toothy animals at home). Make sure the plug is firmly seated in the socket, and there are no signs of heat build-up at the contact area.
- It will not be superfluous to check/replace the CMOS memory battery, which stores the configuration parameters of the PC. If the computer is more than 5 years old, it is recommended to replace the battery even for preventive purposes.
- Remove the case cover and check whether the LED on the motherboard is lit.
- The indicator light is on. it means that the system unit is receiving power.
- If the LED is, but it does not light, check the contacts in the sockets, make sure there are no broken wires.
The next step is to diagnose the button “Start” itself.
Why the computer does not turn on?
It may be that you press the power button on the computer and it does not turn on. What to do in this case?
The reasons why the computer does not turn on there may be several, and before you climb inside the computer should carry out a number of trivial steps that can save time.
First, make sure there is electricity in the outlet 🙂 Maybe just a temporary power outage, and you will disassemble the computer in search of the causes of his “breakage.
Next, check the entire chain from the socket to the power supply unit of the computer. perhaps the pilot (surge protector) is just off.
Or the power cord has popped out of the power supply connector.
Next step. pay attention to the position of the power button on the computer power supply.
Not all computers, or more precisely power supply units, have this button, but if it is present, you may have accidentally pressed it when moving the system unit, or you may have pressed it intentionally, but forgot to turn it on.
If the power is connected to the computer, but when you press the power button nothing happens, then the problem is most likely in the power supply. There is a good chance that it is burned out. There are two ways to check this. use a meter, such as a multimeter, and measure whether or not the power supply gives out anything.
And the second way is simply to replace the power supply with another one borrowed from another computer.
Also don’t forget, that the reason may be the wrong wiring of the power button itself. Wires from the button are connected to special connectors on the motherboard, and if before the problem occurred you should make sure that the wires are connected correctly, because you may have accidentally pulled the wire and it jumped out of the connector.
You can easily find the information on the connectors of your motherboard in its manual.
If replacing the power supply fails, you will need more advanced diagnostics and need to go to a service center, as you can’t do anything at home. Most likely the problem is with the motherboard, and you may need to replace it.
And in conclusion I would like to voice another possible reason, typical for inexpensive motherboards. You might have a situation where the computer does not turn on after you press the power button, although the fans are spinning and some of the LEDs on the computer and motherboard are lit. As a rule, in this case the reason why your computer won’t turn on is the frozen BIOS. To fix the problem you will need to reset the BIOS. There are two ways to do it.
First, all motherboards have a battery that powers the BIOS, which allows you to save its settings even if the computer is turned off. You can remove the battery from the socket on the motherboard, and thus leave the chip BIOS without power for about thirty seconds. As a result the BIOS settings will be reset to defaults and the problem will be solved.
The second way to reset BIOS is to use special connectors on the motherboard. In the manual from your motherboard will certainly be specified which connectors need to be closed to reset BIOS. Usually two connectors are connected with a special sweater. Remove the sweater and connect the other two connectors for a couple of seconds.
I hope that my tips can help you with this problem. If you have had a similar problem and you have solved it in some other way, I will be glad if you share your experiences in the Комментарии и мнения владельцев.
Power supply diagnostics
In some cases, the source of the problem is a PC power supply. it is also worth checking. The procedure is as follows:
- The first thing to check is whether the PSU is switched off. The fact that most modern solutions are equipped with switches: if it is in the “Off” position, no power is supplied to the board and, therefore, there is no reaction to pressing the power button.
Read more: Instructions for capacitor replacement
Why won’t Windows start??
What can a picture on the screen mean?? That at least the PC CPU, RAM, video card and main chips are functioning. That is, technically the computer is ready to work, but for some reason it can not start the operating system. Scenarios reflecting a failure in this case can be.
Suppose the user has the following picture: the computer does not turn on (the screen works), and it is manifested by the following inscriptions on the screen instead of loading Windows. It is extremely important what kind of messages are displayed and what they mean. There can be several basic variants.
There may be problems with the disk drive. In this case you might see something like Reboot and Select Proper Boot Device or Disk Boot Failure.
It is possible that Windows files are corrupted for some reason, for instance due to a computer virus. In this case the command line may appear on the screen, but the graphical components of the operating system will not be loaded. Note that sometimes the same messages appear on the monitor in case of Windows failure as in the case of disk failure.
In both scenarios the problem is quite serious and may require reinstalling the OS or replacing the hard drive. But sometimes it is just a minor glitch, caused by, for example, an unstable contact of the hard disk connectors on the motherboard. This can easily be fixed by checking the related components.
The simplest case is when there is a floppy disk in the floppy disk reader (though they are considered obsolete, but occasionally used). In many PC’s system settings, surprising as it may sound, the option is activated, according to which the operating system must start booting from the floppy disk. Not finding an operating system on it, the computer decides that it is not installed at all and displays a corresponding message. The floppy disk should be removed and the computer should try booting again.
Similar situation. the user has recently reinstalled Windows or added some software samples from the boot disk and has forgotten it in the corresponding floppy disk drive. The system might also be configured to start booting from the CD or DVD drive and it will do this every time until the person removes the drive. Usually if there are no system files on the DVD then you will continue booting from the hard drive. But they can be on the medium in a hidden form for the user, and he may not even know what it is, when the booting of Windows does not go. So when starting the PC you should make sure that no media, neither floppy nor laser, is placed in the readers in any case.
If Windows does not start, you may also have a hardware problem with your hard drive. If it is connected to another PC, connect the hard drive as an additional one, and check if the files are read from it. By the way, it is useful to make copies of the most valuable data to another computer.
Another option is that Windows might boot, but instead of the “Desktop” it will show other pictures or, again, the command line. It means that the disk is fine, but there is a problem with the operating system itself. In this case it is highly probable that the operating system needs to be reinstalled.
In case of any problems with Windows start-up the user must have the boot disk available at hand at all times. It can be a firm installation media from Microsoft or, for example, created by the producer of the computer. In the second case the disk can also contain useful system software. This type of media can be made your own, for example on the basis of free Linux distributions.