HEY THIS REALLY WORKS. FOLLOW ALL THESE AND THE EXTRA DIRECTIONS AT THE BOTTOM! http://www.nvidia.com/view.asp?IO=winxp-2k_archive
Go to the very last 2. download the bottom one and install. Do not freak out when the Windows Icon message comes up. install it no matter what. Restart computer.
Go back and download the second driver from the bottom. Repeat all the above steps.
Then download the LATEST drivers.
(THIS IS FOR NVIDIA GEFORCE CARDS ON XP/2000
after all that go to your HL file and delete the opengl.dll in there. Then go to your System32 file and copy the one out of there. It should be bigger in size than the one in the HL. After u do that it should work.
BIG UPS TO BRACHOLI FOR THE FIRST PART> IT REALLY HELPED OUT!!!