Unfortunately, every game has a different saved game folder default location, and most won’t let you change it. some will save the games into the my games directory under my documents. Some will save in a sub directory under the game’s main directory in c:\program files. Some will do some random crazy shit like create a new directory on some random place and save there, or even occassionally in the system (usually hidden by default) folders under the “roaming” directory.
I hate this. A standard should really be agreed upon by the industry. For windows 7 it should be under a directory with the game’s name under the user’s “My games” directory. Damn it!
So you’ll have to check every game and locate the save directory and copy those files. Once you re-install the games restoring your saves can be as easy as just copying the files back to they respective directories OR as complicated as either having to run the game at least once first (so that the paths are created, or even creating a user in game whose name matches the one you used. It’s really a game by game thing. And it sucks!