This happened to my friend first somehow all his live games stopped working, so he blew his xbox with a firework. Then oneday i went to his house with my xbox to play halo 2 (since his didnt work) he still had his halo 2 so we put that in my xbox and it wouldnt load (same problem on his xbox), so i got my halo 2 and it worked fine. The next day at my house i felt like playin some xbl on halo 2, but when ever i put in my halo 2 the screen turned black then it said "you need to connect the DVD Playback Kit reciever to a controller port to watch movies. Remove disk to continue." So i got my playback kit and put it in the port and it went to the little video that comes up when u put a xbox game in a dvd player and said "This is an Xbox game disk. Please put it in your Xbox to start playing." What is the problem??

NOTE: It started doing that after my friend put his halo 2 disk in my Xbox, and also i tried all my other games live and regular ones and they worked fine.

Clean the bottom of your disk. Pay extra attention to removing fingerprints and goo near the inside of the disk. If that fails its time for a new DVD drive if your disk is not damaged!

like the guy above said, clean ur disc
also
your save game data might have become corrupt. i would try deleting the save game. i know thats a bitch but it MIGHT work. dont be mad at me if it doesnt but if both halo 2's dont work now then that could be the reason. if u have modded xbox then u can backup the save game (or a memory card)

my halo 2 is in really bad shape but my friend said that it isnt the disk when i was about to buy a new one, i think it has something to do with the halo 2 memory