Computer locks up running Prime95

[11427]

Ok,... new K7N2G-L, AMD 2100+, 1gb Samsung PC2700 in dual channel, Raidmax 350 PSU, WD 80gb HD, Lite-On CD/RW, Samsung 3.5" FDD, and a USR Modem.
Have the lastest drivers, BIOS, etc... for the most part everything is fine.
Problem,... I was going to do a little overclocking but before I got started I wanted to make sure everything was stable from the get go.... it's not. Prime95 will run from 10 min to 1 hr, and then it locks up. I do get some horizontal lines on the screen when this happens. I have independantly verified every part of this machine in one of my Asus rigs, everything checks out fine which leads me to believe it is a video problem.
Any thoughts,.... other than a new video card?

 

[FPSguy]

Have you tried running a hardware monitor while running Prime? It might let you know if your temps are too high or your power rails are off.

 

[11427]

According to pcAlert4 temp never goes over 51c, 3.3v is 3.34 - 3.38, 5v is 5.05 - 5.08, and 12v. is 12.00 - 12.06v