Sims 3 requiring activation code again

I recently purchased Sims 3 on disk for my daughter. It installed just fine on the Origin account I was required to set up to install the game. The game played well for a couple months but suddenly when you click on the icon to open the game it comes up with only two options....Activate code or log in as a different user. No matter which option I try, I get "Activation Code" in use but the game is not found in my Origin library. I know when I've had to use activation codes in the past, if I was to delete the game off of the computer and re-install it the activation code will not work because it has already been registered. Any suggestions would be greatly appreciated. I'm really not willing to spend another $30 bucks for a new game since I just purchased this one a couple months ago.