You can fix scratched game by applying toothpaste on the disk. Let it disc have the toothpaste on for like 10 minutes, because this will fill up the scratches on the disc. Wash it off with the tap water until there is no toothpaste left on the disc. Dry the disc with 100% cotton.
Well normally that means you're trying to play the game on an incompatible system, such as trying to play a PS2 game on a PS3 that is not backwards compatible, I don't think it has much to do with scratches.