I used to play a "technically" pirated version of oblivion. That is to say, I owned the game legitimately, but you needed the disk in to play, and for some reason my drive had stopped reading disks properly. So, in order to keep playing without needing to pay again for the game, I downloaded an ISO of the disk off some pirate site via torrent and installed Daemon tools. Now if I wanted to play oblivion (or starcraft, which I think got stolen during a lan party) I just mounted the image.
Not that this really helps you with your dilemma, as you now need to mount the iso every time you boot your pc, but you can play if you have another disk in your drive for some reason.
Oh yeah, I also bought a new drive, so that problem is solved anyway.