Overheat problem?

Hi,

I’m having some strange problems with my home pc. It’s a custom built Athlon XP 1800+, 512mb DDR Ram, 40gb hdd, ATI Radeon 8500, Creative Audigy Player.

Basically when I’m gaming, the system completely freezes. Sometimes after 10-15 mins, sometimes an hour. I’ve moved the PCI cards around, and that seems to have stabilised it a bit, but I’m still having problems.

Also, in some benchmarking software I’ve got, the results are….strange. The FLOPS count is way down, but 3DNOW functions are way up. I don’t have the results to hand right now, but some are fantastic, some rubbish.

Could all this be heat-related? How can I check?

Thanks,
Gary