WC3 crashing issue

Ok, friend just got a new computer, nice system. We built it, loaded XP (after some grief from his hard drive) and all that... blah blah... here's the system:

AMD Athlon 64 3000+
ASUS A8N-E motherboard w/ PCI-E
512MB Corsair PC3200
Antec 350W PSU
nVidia GeForce 6600GT

Alright, so... we get everything loaded, install drivers, etc... go to play Warcraft III. After playing for a little while, his screen suddenly blacks out, though the computer stays on/doesn't restart. We have to manually restart it to get it to work again. We originally thought it was a PSU issue, since his is only a 350W and also only has a 20 pin connector, while his motherboard requires a 24 pin (left the bottom 4 pins blank).

So, we put in a spare 500W I had laying around with a 24 pin connector, doesn't help.

We've changed the keyboard, mouse, monitor (all external devices, in short). I tried putting the RAM from my computer in his... my hard drive... reinstalling XP, reinstalling WC3, etc... still having the issue.

I've tried everything except video card, motherboard, and processor (none of which makes sense to me, because we can run 3d Mark'05 on his computer all day and it doesn't phase it a bit, only WC3).

Are there any known issues with WC3 concerning nVidia cards, or something else I've missed? Help appreciated!

 

Could probably be the video card, mine wouldn't work with 1 game a while back but worked with others. Try getting the latest from www.driverguide.com