I have got the same problem. I have bought the game today in the store, hurried home to finally play the game only to find out some idiots decided I will have to wait playing the game until midnight. Great, this is the only night I have time to play the game. Now I have the retail disc with all data here, and Steam doesn't allow me to use it. I have filed a complaint at Steam just to relief my frustation. If this year Steam-installation was to prevent piracy I tell you this: next year I will consider downloading an illegal copy because I am sick and tired of this ****-in-the-name-of-anti-piracy done to paying customers. If someone from SEGA might read this: STOP DOING BUSINESS WITH STEAM PLEASE, it will only promote more piracy. If someone from STEAM is reading this: stop this bullshit and fire the idiot who came up with this useless stupid ****!!!!