Pretty much any game that is 10 years old, Halo CE PC, Alien vs Predator 2, Half Life (first one), not many games, and you won't even be able to play the latest games, maybe with all graphic settings set to low and maybe hope for 15+ FPS gaming then...otherwise, your PC is ancient, as if you tried upgrading the GPU to a decent midrange modern GPU, that ancient CPU will only bottleneck it. Time for a whole new PC and send that one to the recycling plant.