yesterday someone told in the server that after the game froze, had to restart the PC. i dont remember who, so i will not tag. if someone knows, just tag this post to him.
just create a new Windows user account and, after freeze, CRTL ALT DELETE. you can terminate your session, where you lose all opened programs but no need to restart the system, only the session. or select to change user, where you terminate the COD process in the 2nd account Task Manager. then just change to main user account. you can also log off the 2nd account and log in to the main. this is better than resetting the whole system