Computer Turns Off Few Seconds After Switching On!!!

After a while that my PC had been out of commission, i finally got time to work on it. The trouble–the PC turned off as soon as it is switched on.


At first, I thought it was the power on switch of the PC that was defective. So, i replaced it with a new microswitch but still the problem persisted.

After some research and queries on the possible cause of the trouble, i started diagnosing the problem at the power supply of the PC. Checking the power supply is always first when the trouble is related to power on.


If you have a multi-tester or voltmeter, you can measure the amount of voltage in the terminals of the power supply and compare the readings with the markings on the label of the power supply.

If you’re not satisfied with the reading, go for the temporary replacement of the suspected parts. What i did was to use the power supply of another working PC and connect the terminals of the power supply to my CPU. Bingo! The PC turned on.

Convinced that it is really the power supply that caused the trouble, i bought a new ATX-compatible 600-watt power supply and installed it on my PC.

However, another trouble cropped up and it seems it is no longer related to the power supply.


The PC turned on but after few seconds it will switched off. The trouble may be caused by a corrupted system file or program during start up. I tried first checking whether there is a corrupted program during start-up by disabling the programs after log on.


You can do this by pressing and holding the SHIFT key after clicking your user name or after writing your password and hitting ENTER. Hold the SHIFT key until your desk top and task bar have been loaded. After this you can remove the program app that caused the start up problem.

After doing it, still the PC turned off after few seconds. So, there is another reason for the trouble.


I’ve tried loading the “Last Known Good Configuration” but still the problem persisted. I tried also logging in Safe Mode but still the PC turned off after a while. You can do the said steps by going to the Windows Advanced Menu (press F8 as soon as the PC boots up).


A good reason for the trouble is the system shuts down itself to prevent further damage. Most common cause is the processor heating up due to its failed cooling system or the heat sink is no longer or not in its proper place. The heat sink is attached to the processor by means of thermal paste to effectively pass the heat. Be sure the cooling fan atop the heat sink is functioning.


On my PC, the cooling fan is functioning but earlier i discovered that the heat sink has been detached from the processor. I noticed this when i cleaned the fan of the processor. So, i removed again the heat sink and cleaned it by removing the remnants of the thermal paste using alcohol. I also cleaned the top of the processor.

You may put anew thermal paste between the heat sink and the processor. After ensuring the sink is closely tight to the processor by locking it up, i proceeded a new start up. Whew! My PC is now running and no longer turning off.


One thought on “Computer Turns Off Few Seconds After Switching On!!!

  1. I also encountered this with my old lappy sir jun especially when i used it straight for more than three hours, it will suddenly switched off. inig balik og power on, it will turn off after a few seconds.


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