If you can't run COD4 with that hardware you have problems. First thing would be to go to Windows Update. You may need something and it could be found there. Next thing would be to install drivers. If you can swap out video cards try it. The old 8800 may be dead... r.i.p...... and are you sure you have your keys set up right and then saved the settings ?
Alright, ill try that. Ill also try running COD 4.