There are all sorts of resources here--->
http://support.microsoft.com/?kbid=308041
This is for XP, but many will work for Win 2k as well.
If you can get to the Safe Mode option (Hit F8 at the beginning of the black screen with the white dashed bar at the bottom) and boot into safe mode you know your problems aren't with the basic system or basic drivers.
At that point you can use Last Known Good or System Restore or good old-fashioned troubleshooting to fix the problem.
DaDB