I also have the same problem. Initially I thought it was due to Windows 8 which I recently installed. But to play this game I uninstalled Windows 8 (which cost me $40) and installed Windows 7. To my surprise no luck with the issue. I did this because this never happened when I was running on Windows 7 but after I installed Win8 Origin also updated the game and after that game update my game started freezing at MW challenges.
here are my system details:
Alienware m15x
Intel i7 Quadcore @1.73GHz, 8Gb RAM, 1Gb Video card (ATI mobility radeon 5730), Windows 7 64 bit, No dual screen and matched desktop and in-game resolution, 100% margin. I tried playing with all solutions and suggestions posted on this blog plus some more but never helped.
I really regret wasting my money behind this game. The tech support also did not do anything and closed the ticket without issue being resolved. By the way I waited over an hour to get the support guy on chat and he was not able to help me at all.
I guess EA is a big company and user experience like this is not expected from them. Horrible support for the game.
