The Xbox could be freezing due to a low internet connection or a failed configuration and also a faulty hardware. You need to check the configuration in your router or try to remove the hard drive and then turn the console on to rectify the problem.
Did you try to clean it??? Step 1: Get a clean towel/rag and add soap and water on it Step 2: Wipe the disc with the towel/rag thingy Step 3: Rinse the disc and dry it... If that doesn't work... you're on your own bro!!!
not joking or trying to be funny, but its time to buy a new one. I say this from experience. We went through trying more than 1 copy of certain games and none would work. Finally we broke down and bought a new one, and all the games worked.