My Halo 3 stopped working and I know its not the Xbox.?

[Kyle I]

My Halo 3 disc stopped working all of a sudden. Every time I try to load a map or a campaign level it says "Failed to load content" I recently got the newer multiplayer map pack (Blackout, Ghost Town, Avalanche) so I thought that was the problem. I deleted it and it still did'nt work. I thought the heroic map pack would be corrupted, deleted it still wouldnt work. I also spent the night with a friend (his birthday so I came cause he had a bunch of friends there to play Halo) and I took my disc.We played on system link, blah blah blah, so I think that I came home with a different disc than my own. (Heard of cases where a game would'nt play cause it was'nt the oringinal disc) Im not too sure why it wont play though. Can anyone help me?
I left out that I had it buffed out. (Not one scratch on it before it was buffed out)

 

[Playboi]

if you got someone elses disk then it depends on the condition of the disk and will be recognized by any 360 universally so my guess is you picked up a really scratched disk and you should go ask your friend about it since it happened at the party