PC turning on and off repeatedly

[Bonesdad]

Window 7 64 bit self built. Gigabyte EP45-UD3R with 4 GB of Cosair RAM and a Dual Core E8400 Intel (not OC'd). EVGA 8800 GTS.

My problem: randomly (ALWAYS when I am out of the room and the computer is on, but no programs are running) the PC will begin to shut itself off and turn itself on in an infinite loop. It has NEVER happened while I am using it, even in full blown gaming for and hour or two. It turns off, then turns on for about 2-3 seconds, then off again.

I'd think overheat if it happened while I was using it. I'd think PSU if it happened in front of my eyes (and maybe it still is). Very puzzling to me. My PSU is a Corsair HX520W. System is over 2 years old. I have to shut off the computer via the PSU to get it to respond again, and it turns on normally when I do and performs great for as long as I want to use it.

Any ideas out there?

 

[BoomerD]

I'd suspect the video card. They have a bad reputation for crappy solder joints.

If you're brave, you can try the "oven trick."

http://www.google.com/search?gcx=c&...gc.r_pw.&fp=3b8c2c9e53e6ece3&biw=1495&bih=985

I think I'd exhaust all other possible causes first...and if you have access to a different video card to test your system with...that'd be a good start.

 

[VirtualLarry]

A friend of mine has an EP45-UD3R board, and just recently, he said his computer shut off spontaneously as well. Q8200 CPU. Unsure if he currently has it overclocked, although we've had it up to 3.15 Ghz (450 FSB) stable.

 

[Bonesdad]

Thanks for the input guys, but wouldn't I see the same thing happen, or even happen more often when I'm actually using the PC? I can spend a couple hours on it without event. But leaving it on overnight, I'll come back to off/on/off/on/off/on...

I'll see what I can do about another video card to try...none laying around atm. I may decide to take the entire thing apart and reassemble.

Thanks again.

 

[Puppies04]

While you are taking it to bits see iff there is a bios update aswell to tick another potential issue off the list

 

[mfenn]

While you are taking it to bits see iff there is a bios update aswell to tick another potential issue off the list

Agree with this.

OP, usually when a system has issues at idle but not at load, that means that there is a voltage issue. Do all the shotgun debugging that you have the spare parts for, then try to bump up the vcore a bit.