Actually I think I got a fix, but I'm not sure if its stable. Basically, you have to start the game, go straight to options and NOTHING ELSE, then go full screen, and then windowed. If not, then you have to restart your PC and repeat the steps. Maybe there are background applications running alongside the game, so try turning them off and repeating the steps. If not, try refocusing Medal on the window. Just tell me if it works out for you.