Ok, i bought the game for myself and got my own serial number. I also bought a copy for my friend to use (with a different serial number) but both were bought with my details, and both emails were sent to my email address. For some reason it wouldnt let me use his address. Now when we try to play a multiplayer game i cant add my friend into my game, as it says we are using the same registration! I really dont understand the problem here, we are using different serials, we can both access the lobby online at the same time.. just not join a game together. Any ideas? Maybe a way to completely transfer the game to be registered to him? Please help