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.
Best Regards
Sean C"

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.