Yesterday I was able to load up about half of my videos into Movie Maker and it worked fine.  today I went to add more videos (using MP4 from GoPro Hero3) and I can see in the file the video but they have a little time clock in the middle and won't play.  Now I have a similar problem yesterday, but just had to switch the order of the videos and then they all played backed.  This is getting a bit frustrating, as I've been trying for over an hour to get the rest to work.  Please help!!!