Don't know. Could be a compatibility issue with Win2K. Have you installed SP4? Do you have the latest drivers for your graphics card?
Could also be your graphics card.
Might be temp related as well.
P4 2.6C, Thermalright SP94/Panaflo 92MM M1A, IC7 Max3, Swifty MCX159, 1GB Geil PC4000 Ultra Plat, Radeon 8500, Audigy 2, 2X WD Raptor RAID 0, WD 250GB SE, Plex 708A, 166SDVD, LianLi PC75, XP Pro.