PC Turns on then Instantly Shuts Off


Feb 1, 2010
Hey all,

I've been having a very strange problem lately: When I press the power button on my PC, the fans spin, the lights turn on, then half a second later it shuts off. About 5 seconds later, this process repeats, until I flick the PSU switch.

Recently I moved my PC from one room to another. After I moved it, I didn't use it for about a week or so. When I tried to turn it on after the week, I started getting this problem.

I have an Asus P6T, a Core i7 920, a Radeon HD 4670, a 650W Ultra PSU, and 6GB of DDR3 RAM.
I've gone through a ton of steps to troubleshoot:

1. I've removed the motherboard from the case and installed it on a piece of cardboard.
2. I've tested the computer without the RAM, harddrive, DVD drives, etc. Only the CPU. I still get the same result.
3. I've used a different PSU.
4. I've tried different power outlets.
5. I've reseated the video card, the CPU, and the RAM.

Nothing seems to be working!
Any help is appreciated.



My computer started randomly switching off the second i turned it on last night aswell
Just want to put in my solution that worked for me, i spent about 3 hours taking my computer to pieces and then back together again, put new heat sink, tried different psu's and different power buttons.. my only option was to buy a new motherboard.. however i noticed a lithium battery on the motherboard (im not a computer wiz with hardware) so i popped it out to check it and it had a tiny tiny bit of dust on it, gave it a blow and popped it back in and viola.. computer works and i just saved myself £100~

Check lithium battery on motherboard