Originally posted here by rcgreen
Sounds more like a hardware problem like power
supply fan or processor fan allowing the temperature
to go too high
I would have to agree with this suggestion. I had the same problem when my CPU fan started to go, and it took me a shile to figure out the problem, because as I watched the fan it would start, but after seeing it run I thought nothing of it, until one time I just looked inside the box, and noticed 3 mins after running my CPU fan would give out.