Last night I finally found a way to add games to Game Explorer in Vista that do not install themselves or Windows doesnt add. I tried the manual reg hack but could never get it to work right. After some searching I found a small manager that is in beta but works great. You cant set the ESRB rating or edit the GDF after you have installed it (You can just delete it and start over if you mess up) but it does everything else. It even lets you set the required and recommended system rating!
You can find the manager
here.
You can find the box art, release dates and other info
here and
here.
Just create a directory with a couple of sub-directories to save the box art jpgs and the resource output. After you create it just right click on it in Game Explorer and customize the play command to point to the exe and your set! I have added 4 so far and they work great.
If anyone knows of a better manager let me know. I would like to find one that sets the ESRB also.