I guess your explicit thread title alludes to the game called "Call of Duty - Modern Warfare 2"?
Have you installed the latest patch(es)? On what system do you play it and what Windows version? You play it via Boot Camp or through Wine or something similar?
A more descriptive and precise thread title will help cater to the right audience and get you more responses. (see rule #3 under Minor Problems)
To edit your thread title, just click on the
button on the bottom right of your original post and then click the "Go Advanced" button below your message.
Have you also taken a look at MRoogle, since that question may have been asked several times?