When I try to play an .avi file on windows media player 11, it does not play. No sound no movement! Just the first frame of the video is shown. When I try seeking more in the clip, nothing happens. Worse, same happens to the Movie Maker. On rare occasions, some .avi files do play. Others don't. I've installed many codex but no use. This is not a problem on my other system, but wth! Anyone with any advise?