evilbanshee

What games is it? Does it use Direct3d, Glide, or OpenGL?

Don't use Default OpenGL. Select 3dfx Mini Driver in Half-Life or Counter-Strike. I have a feeling most people experiencing instant crashes in halflife are using default.

Could you provide some details like resolution, default or minigl, XP build, any programs running in background, ...

I only worked on Voodoo3 drivers so I don't know how well the 3dfxunderground version works. Here are some of the responses people gave me for what I've done http://pub84.ezboard.com/f3dfxwindowsxpdriversfrm3.showMessage?topicID=100.topic http://www.voodoofiles.com/4680

Try out the drivers at http://www.3dfxunderground.cjb.net They are based on the drivers I made for the Voodoo3