i wanna sell it so if i uninstall the game does the cd key work when reinstalling again on a new computer?

You should contact EA support about this. In a previous thread no one have a clue about this topic.

weird so call ea?

Yes you can.

If you're on Windows Vista or Windows 7, go to the Games Explorer via the Start Menu. Find the Crysis 2 icon, and right click it. You should see an option to "Deauthorise this Computer". Then the key de-registers from your system, and you're free to take it anywhere else you wish i presume!

Good luck.

Ah you beat me to it lol, was going to say....

As far as I know... from your Crysis 2 Start Menu shortcuts, if you select 'Crysis? 2 - Deauthorize this machine' it will make the game no longer be activated on your computer and give you an 'activation' back. Then someone on another computer can install it.

I reinstalled the game once, cuz I forgot to deinstall the demo first.

I didn't cut the internet connection, and after the deinstallation was done, a window popped up and told me, that the key was reset.