I think there's some misunderstanding here. The way I understand it, SF3 games have a produkt key AND a cd key. One is written as data on batches of cds (I think) and the other is (optionally?) used for multiplayer and has to be entered. Only the multiplayer key would have to be entered and many games don't offer multiplayer, does CM4 ? If CM4 does not allow internet multiplayer, you don't need any key. Unfortunately I haven't ever used a SF3 game so I'm sure someone will be correcting my errors soon