I've done a little search and most seem to be having the opposite problem (no sound), whereas with myself I have sound but no video. I finally got round to copying a whole load of pictures and videos from my DHD onto my computer yesterday. There are 19 videos. Of these, only 6 are working fully (sound + video + thumbnail in Windows) The rest have no preview thumbnail and no video when played, just sound. All were filmed with the same settings. Any ideas!?