uninstall opengl in voodoo 4

Here is my problem. I needed opengl to play nascar 2002, so installed the latest version of opengl. I could get the game to run in opengl mode but the frame rates made it very slow,I uninstalled opengl but it still was there,I uninstalled the 3dfx drivers and reinstalled the 3dfx drivers and you guessed it opengl still there.Can anyone help me out?
pll 350
256 ram
directx 8.1
3dfx 1.04.01(beta) drivers
thanks in advance