I do not play counter strike, so it may not be a demanding game, but I usually shut down all my open programs when I do play some game.
Have you tried changing the resolution in the game to see if it matters?
Are you running multiple monitors or have your system set that way?
If you hit Alt+Space M you can then move the windows with the arrows and the mouse should be tied to it also.
If you think it might help, take a picture with the snipping tool and attach using the paperclip.