Windows Media Player cannot play a portion of the file that you selected because it requires a codec that either could not be downloaded to your computer or is not supported by Windows Media Player.
By default, Windows Media Player downloads codecs automatically when they are needed to play a file. You might receive this message if the feature for automatically downloading codecs was turned off.
After you complete this procedure, try playing the file again. If the audio or video portion of the file is still missing when you play the file, it might require a codec that is not supported by Windows Media Player.