It seems to happen every hour or two. Randomly my game will freeze all sound and movement for ~2 seconds. Then the screen will go completely black and the sound resumes. I can move, shoot and everything else but I have a completely black screen. When I press ESC the menu doesn't come up, but I know it should be there because my mouse appears. I would say it happens while moving, but since I am always moving it may be a coincidence.