Ok so i was playing halo 3, i was on the Storm level or whatever it is.. anyway i get to the end and its going through some sort of cinematic thing, when the xbox dashboard pops up and says that the xbox cant read the disk.. I'd noticed before that there was a big ring that was scratched into the disk before, but it never caused any problems. Also, i tried to play in the Rumble Pit on XBL, and it said that i didnt have all the maps to play, but i'd played there the day before. I dont know if that has anything to do with the disk, but still.. So i was wondering what i could do with the disk to make it work, properly. I did by the game used because i couldnt find a new copy, so i may be able to get a refund for the disk too, but if theres an easy fix, please let me know.