Ouch - the problem may be in the fact that you're using the "latest" nvidia drivers. I know it sounds silly, but oftentimes Nvidia's patches break more than they fix, unless you just use the box to run Quake 3 Arena :)

Perhaps going back a little to a previous version of nvidia's Detonator driver series would help out.

Also, do you have Service Pack 2 installed for Windows 2k?

/P