Simon, Not to knock your advice but CPU can still function even when they are overheating they just loose stability. I think you've been wandering around in the Intel world for a little too long. The either works or doesn't idea is just plain wrong.
I argee with about the Memory alot of times the miss matched memory will cause problems especially if it's from a second or 3rd tier manufacturer.
Also there shouldn't be any remnants of his 98 install on the 2000 system since you can't do a straight upgrade from 98. If it where Xp this would be a different story. The only thing that might be a concern in this part is that he may have left the old file system intact and had a virus or two on the system when he did. Therefore infecting the new OS like it did the old.
My recommendation is still to look at the system and check the fans. If they are fine and you system still does it after pulling out the ram then look at downloading the VIA Drivers from viatech.com The VIA chipsets have some PCI compatiliblty issues with Windows 2K. Also have you done the Service Pack updates to 2000?
