It happens 2 me also when playing 2K games ; which have been modified from original DOS games; Win 7 doesn't like DosShell. It will knock the game down 2 bottom strip; when u click it comes back in small screen; SAVE then restart a load 2 resume . On my sys - what causes it is NativeHost.exe & if u have ur computer set 2 automatic updates of Win; any update 2 .FramesWork Net . I had 2 reset updates 2 start at a certain time; because if u set u notify , it interfers w/game.