Please remember to post whether this worked for you, others may be having the same problem and may look for this thread for guidance. If it was as simple as the aforementioned by the 2 prior posters, then others with the same problem as you will be able to solve it that much more quickly.
If not, then the problem may still be resolved for others by ending the process in the task manager. Also, if you don't see the Combat Arms process in the first tab, then go to the next tab and search for a process called: ENGINE.exe
And if there are still problems, remember one very important thing:
I like pie. o3o