I've been using Movie Maker to edit videos I've taken with my iPhone. All I do is cut out dead air, and divide files into two for YouTube upload. All this has been just fine. However, lately I've been running into a really odd and frustrating problem. I'll open up my video file with Movie Maker, and wait for it to process. When finished, I'll see the timeline on the right, with the little waveforms indicating audio. I press play, so I can follow along the video and figure out where I want to make cuts. Here's the problem. I'll hear a little chirp - a brief blast of digital noise - and then nothing. The video is totally mute. I can stop the video, and it's still mute. I'll close and reload, and it's still mute. If I save it as a Movie Maker file and reload, there's still no audio. This is an occasional problem, but is happening more and more often, and I simply don't know what to do.