Re: Can I sell my Sims3

I will!  But does that mean that I can't do anything to let someone else play that game?

Once the registration has been linked to a player account, it is permanent.  You could resign your account to someone else, if you had no further interest in any EA products from now on, but if EA finds out your account is being used by someone else, they'll probably shut it down anyway, since they don't want you sharing it that way.