Media Direct failure please help

ok, i need some help with my dell media direct software not playing my bluray discs.  I'll try and explain what's happening as best i can.  I will insert a bluray disk and the menu will load as normal and some of the features on the disk will play. However, many times some won't and here's what happens.  The screen of the media player will be black like right befor the movie starts and the i can hear the disk begin to spin, it will then stop and begin spinning again.  After another stop and start the media player screen (where the movie should be playing) will be green and the audio track will still be playing without video.  This isn't a problem with the disks as i have played them on this machine befor (sometimes the movies will play and sometimes they won't).  I don't think it's my cable, because the rest of my screen in uneffected only in the Media direct player will this happen. And it isn't the drive because it will detect the disk and load the menues and play sometimes.  i can only assume it's the software.  Please i'm not making this up this problem is really strating to get to me.  if anyone has any ideas it would be very helpful.