1. From the Xbox 360 dashboard, go to My Xbox.
2. Scroll to System Settings.
3. Choose Memory.
4. Open the storage device you are saving to. (For most users, this should be the Xbox Hard Drive).
5. Choose Games.
6. Select the game you are backing up.
7. You should see an Auto Save file and a Backup Auto Save file listed here.
8. Please delete the Auto Save file, then restart the game. You will be prompted to use the backup save file and you should then be able to continue the game.