[Solved] Running Games from Different Operating Systems without Reinstalling

So for the longest time my main computer was Windows Vista and that is where all of my software and video games are installed. Now, I have a new hard drive with Windows 7 on it, and I don't really want to have to install Fallout 3 on that too since it takes up 6 GB of space. What I am wondering is if there is any way to run Fallout 3 on Windows 7, which is installed on Vista without having to reinstall on Windows 7.

nope, when you install the game it adds data to the registry

"Most" installed games (and "most" programs) will simply run in the new OS. Just find the executable in the filesystem. You wont have shortcuts in your start menu or wherever, but you can easily put them there, or put a shortcut on the desktop as you probably know.

That's just not true. Most programs nowadays set up various keys in the Registry and just won't work (certainly won't work properly) if they are not present. A very few, mainly older or very simple, programs may work in the way you describe but they are very much the exception.

The best thing to do is to follow the procedure outlined by Herr_Koos.

Best answer selected by EchoXero.