plz help me :(

I have a fairly serious problem. Recently I installed the drivers for graphics cards (on old ones), after this there were some problems such as no text in movies, I reinstalled drivers, but when removed it I removed also another nvidia drivers (nForce etc). I installed everything again, and now when i play (formerly a stable 76 fps), there are the periods that everything is working fine, then drops to 10-30 fps, in addition to all I've got feeling that even at constant 76 fps (although its rarely now) game is running at 20-30 fps and whit continuous warps.

Do you have any idea how to fix it? (Win Vista, gf 8400M, 2x1,9 amd turion) <- laptop

btw, sorry for english...