Usually Pam, the deauthorization is like this: Say you have a large household and put your Sims game on five PC's in the house which is the authorization limit. Now if you buy a new computer and want to have the game on that one instead of say the oldest PC in the house, you would need to deauthorize it from the old PC before you can install it on the new PC. It's to stop people just downloading the game to all their friends' computers.