Can someone tell me what's wrong?

Oddly enough, I can run ports like GLLegacy in 3DFX Glide mode, but when I try to run it in OpenGL mode, the computer crashes and I have to reboot.
It's not just this particular port, but all my GL ports won't run. I don't know what in the hell's wrong so I thought I'd ask here.
?

Reduce your Hardware Acceleration (95, 98 Me), Performance Boost (NT) or Troubleshooting (2000) setting down to None, see if that alters problem.

Check and seee if you have the latest driver for your card.