Unknown Disk Format problem

[Juushiro]

I have no idea why, but whenver I put my GTA:SA CD, it's like my CD Drive doesn't even detect it. It used to show a little GTA icon, and now it just says DVD/CD-RW Drive. When I try to start up San Andreas, it says: The disk in Drive D: is not formatted properly. Please check the disk, and reformat if necessary. And if I press cancel, nothing happens and I have to manually cut off GTASA.exe, or if I press continue, then it just says no disk inserted, please insert the CD/DVD. The CD is practically scratchless, I know it's not my CD Drive, because any other CD works fine. I've tried rebooting, and I've tried un installing GTA, and it only worked long enough for me to install it, and play a view times. It doesn't freeze or suddenly turn off the program, it just won't start up. Can anyone help me?