Today I discovered somthing extremely handy if you are a Steam user for games on Windows. This does require that you already store your steam games on a seperate partition or disk to your OS installation. I do that to keep all the games off my rather small 128GB SSD drive which contains just the OS. If you don’t have steam on a seperate drive, you would have to backup all the content in Steam (right click on a game and choose backup) and then reinstall Steam on another drive, e.g. D: instead of C:.
If you have installed Steam on another drive, you are in luck. All you need to do is reinstall Windows (clean install is fine, format the C: drive and install a fresh copy), then you just download and install Steam into the same location it was previously. Lo and behold, Steam sees all your games and steam apps, and when it starts up you will see all your games ready and waiting. Pretty neat huh? If you buy games exclusively through Steam, this makes reinstalling the OS much easier. I would recommend that you backup your Save games just in case.