These frequently happen sometime when you are using both the computer as well as projector an the display sometime is not being projected by the projector but it is shown only on the computer as there are some function key by pressing the display can be seen only on the TV and not on the computer or else the other way is only get a VGA cable and attach directly to yours system and not to the monitor so you can only use the TV as your main desktop or else try using another media player like Media codec if it can display on both the screens.