System lockup(no reboot)

[KGainey]

Hey...
I've been looking around on here for answers for about a week or so and finally decided to post a question.

Specs:
AMD Sempron 2800+
ABIT KU8
1.5 GB DDR
160GB Maxtor diamondback
350W Ultra(I know, I know) PSU

This is my first build and it has been giving me problems since I first booted it up. I think I can safely rule out software issues, seeing as how it locks up on windows, FC3, and ubuntu. It typically locks up after being on for about an hour(+/- 20 min.). The CPU idles at ~26C, and under load ~33C. According to ABIT's monitoring software, the "PWM" is at around 37C after running for a while(not sure what PWM actually is). Any suggestions or ideas would be greatly appreciated. If you need any more info, please ask. Thanks!

--Kyle

 

[24/7 Gamer]

Could be a problem with your memory, run Memtest and show us your results.

 

[KGainey]

okay...memtest is about 80% finished for the first pass...how long should I let it run?

--Kyle

Update:
memtest ran through 2 passes w/o error. Any other ideas?

 

[iam_not_2fast4u]

what are your temps?

 

[KGainey]

CPU(idle): 26C
CPU(under load): 33C
PWM: 37C
HDD: 30C

Update: I'm thinking it's a video card problem. I just realized that when it locks up, if I leave it running, it will eventually update the screen(I know by the clock), and then freeze again. The sound just stops, no stuttering, the keyboard stops responding as well, no change when I hit capslock/numlock. I'll try to get a loaner card from someone and see if that'll sort it out... Thanks for your responses so far.

 

[KGainey]

any more ideas?