Why does my xbox keep freezing?

My xbox360 has some issues. my gears of war 2 disc keeps freezing whenever i try to play. i know its not the disc because i have cleaned it, tried other discs from friends, and even bought a brand new gears of war 2. but the thing is, if its my xbox, every other game that i own works perfectly on my console. its only my gears of war 2 that won't work. i have 3 discs at my house. my cleaned one says "disc is unreadable", my brand new one freezes, and my borrowed disc from a friends also says "disc is unreadable" all errors seem to happen 2 minutes into a public match and 5 minutes into a private match. CAN ANYONE TELL ME HOW TO FIX THIS?!?!?