Ok.
Gamergate installer is a free download from gamergate, its very small, and quick to do. When you buy, if you don't have this, install it.
Then login to ur gamergate account through the downloader. If you have purchased the game, an option will appear for you to download the game.
Once finished, it will then give you an option to install, install it, and you will no longerr need the net for the game.
As for the CD, It depends, if you know what an ip address is, its the name of your internet, and every one is different, if you share a connection with two computers, the games will work on both. You will be able to install games that are using UR internet, but it will not work on a computer that has different internet from when it was first installed.
To get the game on another ip address, you must contact gamersgate.
lol, sorry if im not being clear.