My little brothers Xbox seems to have put a faint line in the disc and now isn't letting the game play. I can get into the game but it plays for a minute or two and then restarts and says there may be a problem with the hard drive. We reinstalled the game and tried again but there was no change in the results. Anyone ever heard of this or have any suggestions? If not, what's the chances that GameStop lets him exchange it for a new one? TIA.