PC Craziness

Okay. I’m going crazy with my friend’s PC. I brought him over a 300W Enhance power supply. Not sure on how good Enhance is, but it should’ve worked, really. His machine is STILL FREEZING UP, randomly in normal use, and ALWAYS when trying to run Serious Sam 2. I’m very certain it’s not the game, as regular Windows use causes lock-ups. It must be power or memory… as the video card starts to “work”, it freezes. Maybe the PSU just isn’t pushing enough juice to the card? ARGH!