Shutting down -reason unknown

[samhfoley]

My old PC, which I donated to my father in-law is now periodically shutting down spontaneously for no reason known to me. I ran memtest on the memory overnight, 21 passes 0 errors. Anything else I should check?
Win 7 64 bit, all updates and service packs installed
ASUS P5K-E/WIFI-AP
have to check on the processor, Quad core, but specifics escape me at the moment

Ideas?

 

[striker410]

Hmm, tough to say. Probably some power shortage. I'd unplug everything and breadboard according to this guide here: http://www.tomshardware.com/forum/261145-31-perform-steps-posting-boot-video-problems Should help wittle things down.

Follow that, see what turns up. If nothing we'll try a few more things.

 

[mightymaxio]

Test it with a power supply tester and make sure the power supply isnt failing first. They are like 15$ at bestbuy or radioshack.

 

[samhfoley]

when I took it apart and was checking the connections, every time the power supply cord to the MB was barely tapped it would restart. I am thinking its probably a power supply issue. Wish I had a Radio Shack or Best Buy in Japan.

 

[jeffjeff666]

Probably power supply issue.

I had random restarts especially under heavy load. Turned out to be the memory timings that were wrong. memtest was not giving any errors.

 

[samhfoley]

No heavy load here. This guy hardly uses the PC at all. Excel, Word, that's about as heavy as it gets over there.