I got this "choppy graphics" problem with every OpenGL/D3D game(like Half Life, UFO: Alien Invasion) after i reinstaled windows(xp sp3)
i had that problem before and i fixed it, but i dont remember how...
i already have latest driver of Nvidia Geforce4 with AGP8X graphics card(i have driver scanner that tells me if i have driver that needs to update)
unsupported gfx by the looks of it.
thats a seriously old setup and its likely even with up to date drivers it wont run games that require shader model 2 even emulated in opengl. which i assume your trying to do.