I recently started playing the halo 3 campaign again, and when I reach the 3rd mission, or load some of the later missions, I get the message "disc unreadable" and it brings me to dashboard. The same problem occurs for some of the online maps, but not all of them. I've tried my friend's disc and also removed my hard drive with no results. I'm still using the same xbox that i played the game on originally, and i have never had problems for this or any other game before now. No other games i own have this problem. Does anybody else have a similar problem or have any solutions or suggestions on how to fix this (short of repair, as I would rather not play halo 3 than pay the $99, since I am out of warranty)?