Originally Posted by Coded I checked the mobo at iwill and it says "Supports CPU Speed From 600 MHz up to 1.2GHz". As the athlon is at 1.5 (not clocked - i dnt think) could this effect it?
If its an Athlon 1500+ then it doesnt really run at 1.5Ghz, it will run slower, thats how AMD works.
Another thing todo would be either load up Motherboard Monitor 5 or check the voltages of your PSU in the BIOS, I used to have a problem like what you describe (didn't have an error message though) and the comp would reset as the PSU wasn't providing enough juice under load.
Thats a good thing to check first, try testing some of his components in another comp and try running his rig on a different power supply, you never know, you just gotta see what happens.
Hope that helps