Re: Bought my Sims 3 from Amazon as a digital download, but it won't allow me to register the game.

Log in to your Amazon's account, go to Your Games and Software Library, the code for the game is there. Make sure you are typing it correctly, if it still gives you issues, on the first page of The Sims 3 here on Answer HQ is a post there that says: [READ FIRST] Known issues, guides and FAQs. There's information there about invalid codes.