I just downladed it and i made a stardock account but it will not com up it just wants me to registure it my uncle said it wasnt always like with gamestop so he dont know how ether

I believe that you will need to activate the game through Steam in order to play it. I had previously purchased, downloaded and played all versions directly through GameStop, but when I purchased Rebellion here are the instructions I got when I hit "play":

1. Download the Steam software from: http://store.steampowered.com/about/
2. Install the Steam software.
3. Log-in or create a Steam account.
4. Click on the "Games" menu and select "Activate a Product on Steam".
5. Click Next and agree to the Steam Subscriber Agreement.
6. Enter the Product Code above into the Product Code field.
7. Click Next and the game will be added to your Steam account and begin to download.

A couple of notes.  First, you will need your product code copied and ready to paste.  Second, I had a problem with Steam in that it would not install the client (the actual software you use to register/activate the game) until I had disabled my security software.  You will know that you have done this correctly because it opens a pop-up window separate from the main Steam site.

Hope this helps.  Good luck!