Hi!
AGEOD will help you with this, i'm sure. They are very nice guys
But as Boudi says, there is no need to redownload.
That is an extraordinary measure you can ask for in case of crash of any special problem.
The file you downloaded (and will re download again) is the full game.
You are allowed (and its highly recommended) to save it somewhere safe, like burning it on a CD/DVD, or on a memory stick or external HD.
Put the game serial beside it in a txt file like Boudi recommends and you will always have your game safe and ready to be installed and played anywhere and anytime
Regards