...Help?

My computer is behaving miserably: any time I put any significant processor load on it, it crashes and reboots. It'll open programs and handle normal tasks readily enough, but if I try to use it for games, for example, or even converting audio file formats, the crash happens. The error reports keep blaming drivers, but I can't possibly imagine how device drivers are affecting so many different things, most of which they have nothing to do with. I initially thought it was heat, and it may still be... I'm checking temperature readouts now. I know my heatsink fan is working, as are the chassis and power supply fans (despite my utility's insistence), but according to benchmarks my processor should be functional up to 80C at least.

I'm really at a loss here. Heeeelp.


UPDATE: According to my probe utility, the CPU temperature was 66C when my computer cut out again -- which is supposed to be well within the parameters of the chip. I'm stumped.