i'm in the same boat as you. i bought the game when it came out too and i just re-installed it. first i had a problem with the password for my account, which i eventually took care of. after i fixed that, i then tried registering my game with no luck. even the expansion key doesnt work! customer support is nonexistent as far as i'm concerned. its not fair, but that just how it is.

did you re-install the game on another computer by any chance? because i did, which is probaly the reason.