Clevo is correct. This is basically a clash between Aero and a Movie Edit Pro display mode. The problem should only occur with one particular display mode of MEP (overlay mode) which Aero doesn't properly support. Try this: When in Movie Edit Pro, go into the program settings ("Y" key) and switch to the "Display options" tab. Switch the video mode for the preview in the arranger to a different mode, ideally the hardware acceleration mode (if you have sufficient graphics hardware that supports it). That should enable you to keep using Aero with MEP.