Remember the video you might have saved just now is in Flash Video Format. It really is the normal file format YouTube use to perform video on their web site. So, your Wmp might unable to play the movie. But no stress, what you have to do is simply go to google.com and search for "flv player" and there are couples of Free player available. Simply download and set it up in your computer you'll be able to watch the movie you saved just now.