I don't remember GameRail being difficult to install, so I'm not sure where you're having problems.
Where, specifically, are you getting hung up at?
If you're having trouble with the install not finishing, the installer "installs" new (virtual) hardware, make sure you're logged in as an administrator on Windows, and if the install pauses, alt-tab and try to find a dialog for installing new hardware, then click the button to install it. Sometimes those pop up in the background.
I also remember whatever method GameRail uses to draw windows doesn't like to draw over 3D areas or any kind of graphically complex program, so if you run the installer and nothing happens, minimize everything and alt-tab around to try to find the window. After installation, GameRail should run on its own, and you should just log in with the info you signed up on their site with. It will automatically route gaming traffic as long as it's running.
If you need any more help, please elaborate and I'll try to answer.