I had a problem like this with Shift 1. When I tried to log in online the game told me that the CD-Key is already used. I wrote a mail to the ea-customer suport with the description and a screenshot of the CD-Key report. They gave me a new Code for Shift and NfS Most Wanted. I just had to reinstall and put the new key in the windows registry.

HomeSummaryRelease DataGame CreditsAlso PlayingCollection Stats Guides Q&A CheatsCheatsAchievements Reviews MediaImagesVideos Board UnlockablesReward CarsBeat the listed event in career mode or obtain the listed level to unlock the corresponding car. The invitationals require only podium (top 3) finishes. UnlockableHow to UnlockBMW M3 GT3 ALMSBeat the Endurance Challenge of ChampionsChevrolet Corvette Z06Beat the Modern B InvitationalFalken Tire Porche 911 GT3 RSRDriver Level 15Lotus EliseBeat the Modern C InvitationalMcLaren MP4-12CBeat the Modern A InvitationalMonster Energy/Falken Tire Ford Mustang GTBeat the Drift World ChampionshipNFS Shelby Terlingua Ford MustangDriver Level 11Team NFS BMW Z4 GT3Beat FIA GT3 ChampionshipTeam NFS Mazda RX-7Beat Works ChampionshipTeam NFS Mazda RX-8 DriftDriver Level 5Team NFS RTRX Ford MustangBeat the Muscle World ChampionshipTeam NFS Time Attack AWD Scion tCBeat Time Attack World ChampionshipTeam NFS Toyota Corrola AE86Beat the Retro World Championship 5 30 Know Something We Don't?You can submit new cheats for this game and help our users gain an edge.