Why is Black Ops crashing after EVERY multiplayer match I play?

Black ops used to run fine. Now, ever since Escalation came out (I did NOT download it yet), after every multiplayer match it resorts to the main multiplayer screen, frozen. I am unable to do anything. The music still plays, but I cannot do a thing. Pressing the middle xbox button yields the correct noise, but no menu is displayed. After about 3 minutes of waiting it will go to a black screen, and the black ops loading animation will display. After that, it returns to the main multiplayer screen, frozen still. This is an infinite loop. The only way to get out of it is: 1. Turn off the xbox. 2. Open the disc tray, and 3. When the screen goes black, with the loading animation, I have a small window of opportunity to press the xbox middle button and select "Y" for dashboard. My disc is near perfection, I have treated it with the utmost care and upon inspection, the disc is free of scratches, finger prints, dirt, dust, beverages, you name it. It looks brand new. It seems in my experience, NOTHING WORKS THE WAY IT IS SUPPOSED TO. This is unacceptable. I cannot play it like this. I am pulling my hair out trying to play this game and after every match it just locks up. I bought my xbox a year ago so it is fairly new. Why is this happening and how can i resolve this?