How to fix a computer that turns on and then turns off

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Alejandra Rangel
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What to do when the computer turns off during the boot process. The computer turns itself off immediately or at some point before the operating system loads? In this case, it could be anything from an electrical short to a serious hardware problem.


As there are several reasons why yours PC may shut down by itself during the boot process, it is important to go through a logical troubleshooting process like the one we have outlined below.



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How to fix a computer that turns on and then turns off

This process may take a few minutes depending on why the computer turns off so quickly after being turned on.

Check the power supply voltage. If the input voltage of the power supply does not match what is needed to power your device, the computer may not be able to stay on. Chances are your computer won't turn on at all if the voltage is wrong, the wrong power voltage could also cause the computer to shut down by itself.


Make sure your computer doesn't overheat to the point of turning off. Leave the computer vents free and check that they are not so dirty that they do not allow the passage of air, do not place it in very hot places and make sure that the fan is working.

Check for electrical short circuits inside the computer. This is often the cause of the problem when the computer turns on for a second or two but then shuts down completely. Inspect the inside of the computer for any problems that may be causing short circuits.



Test your power supply. Just because the computer has turned on for a while doesn't mean that the computer's power supply is working properly. The power supply tends to cause more problems than any other piece of hardware and is often the cause of a computer's automatic shutdown. Test if the power supply fails. After checking, let the computer charge for at least half an hour before turning it on.


Try the power button. If the power button is shorted or doesn't fit well, it could be the reason why the computer turns itself off. Replace the power button if you suspect it is not working properly.

Reposition all inside your computer. The reset will fix any connections inside the computer that may have loosened over time.

Try repositioning the following and then see if your computer stays on:


  • Reseat all power cords
  • Reseat the memory modules
  • Reseat any expansion cards

Disconnect and reconnect the keyboard and mouse as well. There is little chance that either of them is the cause of this problem, but we cannot overlook this eventuality.

Only start your PC with essential hardware. The purpose here is to remove as much hardware as possible and turn the computer back on. If the computer turns on and stays on, with only essential hardware, go to the next paragraph. If the computer keeps shutting down by itself, move forward one paragraph. This troubleshooting step is easy enough for anyone to complete, requires no special tools, and could provide a lot of valuable information. This is not a step to skip if, after all of the above steps, the computer still shuts down by itself.



Reinstall any non-essential hardware components, one component at a time, testing the computer after each installation. Since the PC is powered on only with essential hardware installed, these components work fine. This means that one of the removed devices is causing the computer to shut down by itself. By reinstalling each device on your computer and testing after each installation, you will eventually find the hardware that caused the problem. Replace the defective hardware after identifying it.


Test your PC using a power-on self-diagnosis card. If your computer keeps shutting down on its own with only essential PC hardware installed, a POST card will help you identify which remaining hardware is to be uninstalled. If you don't already have it and aren't willing to buy a POST card, go to the last step.

Replace each essential piece of hardware on your computer with identical or equivalent “known good” hardware, one component at a time, to determine which piece of hardware causes the computer to shut down automatically. Test after each hardware replacement to determine which device is defective. Since we do not have a collection of spare parts at home, to do this we just have to take our computer to a technician.


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Further Reading:

  • How to fix a computer that shows no signs of life
  • How to troubleshoot stopping, freezing, and restarting during POST
  • How to fix a computer that won't turn on
  • Samsung Galaxy A50 turns itself off and won't turn on
  • How to fix a computer that won't boot in safe mode
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