me and my friend started halo on the XBox a months ago and every now and again i go over for a day and play. but we've got stuck on the 4th level i think. literally stuck. the discs been somehow scratched but you can't see any scratches on the disc. its really frustrating as our total playing time was about 14-17 hours. theres no way we can play the level. is there any way to swap it for another copy at Game or anything? he told me that you could do something like that.