I have 64 bit windows 7.  I started noticing my mp4 videos were not opening up correctly  after i rated the video 5 stars.  So now, the videos I rated 5 stars I can only see for like a second and then they disappear.  I removed the rating but the video is still not opening up correctly.  This only happened to the mp4's I rated 5 stars so I know it has something to do with this.  Please help.