PC turns off after a few seconds of being on

This problem has happened before. After a black out or something the computer would turn itself on and off continuously until I unplugged it. Just last week it started happening regularly. The computer would start up, but the lights on the motherboard would go off after a few seconds and everything else worked fine. I thought maybe I just needed to clean the dust out of the PC, so I did. I took out the CPU heat sink and cleaned it. I tried to put it back in, but I noticed that the plastic part on the bottom of the heat sink was broken and could not be properly placed back in. I also noticed that the thermal paste was all gone.

I know I'll probably need to buy a new heat sink so feel free to recommend some. Any ideas what the problem before that was?

E8400 stock clock
2 x 1GB 1066
850W Cooler Master

Tell temps.

I never took the temperature of anything on that pc. And I can't do it now because it turns off after 3 seconds of being on.

does it start to load windows then crash?

It does not load Windows at all. My screen stays blank the 2 seconds the computer stays on.

It does not load Windows at all. My screen stays blank the 2 seconds the computer stays on.

Someone should delete the post above. Why do I not have permission to delete my own posts?

this problem seems very vague. it can be many things

try clearing your cmos first off and try booting again

if you have extra parts laying around or an extra similar computer that your willing to temperately sacrifice
so you can troubleshoot by swapping parts and ruling out possible problems.

CMOS has been cleared. The problem still remains. Sadly what I'm typing on is my sister's computer and she won't let me use it to troubleshoot.

Looks like you need a new power supply.


but a dead cpu or mobo can have the same symptom

cpu, mobo and psu are the likely problems

I say power supply. Check that first.

If the CPU fan is not set properly and there is no thermal paste, it is very possible the CPU is overheating.

First things first, get a new CPU heatsink and Fan, if problem persists after that, replace the PSU, still having issues get a new CPU.
If none of that works.. Get a new MOBO, and a friggin UPS.

my friend had that issue, his core i7 computer would turn off 5 minutes after being on unless it was on its side. and it ran really slow when it was on. it ended up that his stock intel heatsink had un pinned because they suck.

Try putting on some thermal paste, and holding the cooler on the CPU firmly so it works well, if this solves it you can be pretty sure its an overheating problem, just get a new cooler