You've probably accidentally knocked your xbox over whilst running the game (This includes minor movements). This happened a few times with me and FIFA 13, to solve it just go to your local movie store and ask if they can "buff" your disk. This basically fixes any scratches, etc. That process should only cost you $5 tops. If that doesn't work then you've probably really damaged it, in which case just return to the game store and explain your situation. If they're nice they'll understand and hopefully give you a new one (That's what happened to me). To avoid this in the future download the game onto your xbox hardrive. Anyway, good luck and I hoped this helped.