Originally Posted by MOH
I had thought part of the whole "Games for Windows" thing meant there were standard folders things were supposed to go into, somewhere under My Documents.
When I couldn't find them there, I presumed since they were linked in with GFWL they were stored online somewhere. Have you tried logging in again with the same GFWL account?
Failing that, maybe they're somewhere under the GFWL folder?
They're in the hidden "Local Settings" folder underneath "Documents and Settings\<username>".
I recently had to reinstall my machine, so took a backup of that folder. However, there's a step you have to perform. When you start a new game, it create a uniquely named folder - something like "user_982er2432". When you back up, then install again and start a new game, a new uniquely named folder is created. You need to copy your old saves from the original folder to the new one.
It's possible that you still have your original saves on the machine. If I get a chance later, I'll add more detail (the above is just based on memory).