A retail CD Key may only be registered to one Steam Account. CD Keys are associated with your Steam Account, not your computer.

If you are certain you have not registered your CD Key to a Steam account in the past please see the CD Key Reset Process topic for instructions.

If you have already activated your CD Key on a Steam account but do not recall the login information for the account your CD Key is registered to, see the Contact VALVe Billing and Support topic for instructions to contact Steam and provide all of the following information:
  • A scan or digital photo of the CD Key
  • Any Steam account usernames you may have used
  • Any contact e-mail addresses you may have used