Anyway, eventually I just took off the side of the pc case and pointed a regular fan inside and that worked okay for a week or so, but then the crashes started again, so I just assumed the fan on the video card wasnt working anymore.
So earlier today I went out and bought a new video card, a radeon x1650 pro, and installed it. I played WoW for maybe 5 minutes before my pc crashed, so I opened it up and felt the new video card and it was HOT. Nearly burnt myself.
With two internal fans working fine, and the side of the case open with a room fan blowing inside, I'd say it's pretty clear that I don't have any cooling problems. Could it be the motherboard maybe? Is my brand new videocard at risk of being damaged just by using it?