randomly shuts down

[demon42]

Please help!
My computer randomly shuts down. Sometimes it lasts 2 minutes, other times it lasts up to 10 or 15 hours, but it always shuts off. Usually it happens when the system is idling, but not always.
I have both been watching and logging my cpu temp when it shuts down, and it's [edit:]NOT overheating.
I have even had the machine power down in the middle of a repair console session (while running chkdsk)
My XP is set not to reboot on BSoD, none is shown, and there are no entries for the reboot in the error log.
Currently, my system is:

ASUS A7N8X-X mobo
Radeon 9600LE graphics
Geil 512MB 3200
2 hard drives (60 & 80 gig)
DVD-R, CD R/W

After talking to a few people, i decided it had to be my power supply, so I bought the Thermaltake 480W. The machine shut down about 3 minutes after the first boot and resumed its normal buggy behavior.

Any ideas on what is going on with my machine? HD failure? Ram problems? How can i check to see if these are the culprit?

Thanks in advance

 

[Fern]

Above, you say it's overheating? Did you mean NOT OH?

Run Memtest86 to check your ram. Get it HERE

Go to the website of you HD manufacturers to get free diag proggies for checking them.


Fern

 

[Cheetah8799]

A coworker had the same problem with a new power supply he put in his computer. Turns out the 12v rail was pretty low and was causing the mobo or something to decide it didn't have enough voltage, so it just shut down when playing games... So make sure to check the voltage output, you can see it in the BIOS, usually under the "System Health" menu.

Other than that, I'd guess it could be bad ram, which memtest86 can check for. Or maybe the cpu or ram is overheating I suppose. I doubt the hard drive would cause it to turn off. If you think that could be it, then boot from a Knoppix CD with the hard drive removed and see if it turns off then.