And sadly, it is my copy of The Orange Box. I bought it 5 years ago, installed it once, got a no CD crack and then put it away. Subsequently I tried installing it again on another PC, but the system refused to detect the disk, and simply says 'Please insert a disc' if you try accessing the drive. I get the same problem no matter where I try, and the disk does not look damaged or scratched in any way.
Is there a way to read it, or recover it as an ISO?