I sent an email to WB asking if the 5 installs can be reset like on other games once they are used up, here is the reply so we all know:
"Thank you for contacting tech support. Unfortunetly the code can only be used on 5 PC. If you have reached your limit there isn't a way to reset the code. To install the game onto another PC you will have to purchase the game again.
But that sounds like you install the game on 5 different PC's but can install on the same PC as many times as you like? Thank god for that revoke tool. I have used 2 already, one was a new PC and the 2nd was a fresh win 7 install. The 3rd will be win 8.