As far as I know, and I do play cod4....windows 7 can't run the game due to pb issues...as of yet the issue is to be resolved...it has to do with the PB service and windows 7...there is a small workaround, and that means you have to run the PB services...both A and B before launching the game.....but then when you exit the game you have to do again....for some this works....for others it will will allow only about 20 minutes of play before you get kicked......hope this helps ya