I receive a "Duplicate CD Key" error when I try to register my CD Key - what should I do?
If you purchased a new retail game and are receiving Duplicate CD Key error, please contact the retailer where the game was purchased to obtain a new copy of the game.
If the retailer is unable or unwilling to assist you, it is recommended that you contact the game's support for further assistance.
A retail CD Key may only be registered to one Steam Account. CD Keys are associated with your Steam Account, not the computer on which the game is installed.
Please see the Resetting a Lost Password article for instructions to retrieve your lost Steam account if it is possible that you have registered your CD Key in the past.