http://www.microsoft.com/windows/windowsmedia/player/faq/codec.mspxThe following questions have been added or updated in the Windows Media Player Using codecs FAQ.© 2006 Microsoft Corporation. All rights reserved.http://www.microsoft.com/windows/windowsmedia/player/faq/codec.mspx#14_1A codec is software that is used to compress or decompress a digital media file, such as a song or video. Content creators use codecs because a compr...Wed, 17 May 2006 15:00:00 GMThttp://www.microsoft.com/windows/windowsmedia/player/faq/codec.mspx#14_2You are probably trying to play a file that uses a codec that is not on your computer. When you try to play a file that uses a codec that is not on y...Wed, 17 May 2006 15:00:00 GMThttp://www.microsoft.com/windows/windowsmedia/player/faq/codec.mspx#14_3When trying to find the right codec for a particular file, you can use WMPlugins.com or other Web sites. Typically, you should start with WMPlugins.c...Wed, 17 May 2006 15:00:00 GMThttp://www.microsoft.com/windows/windowsmedia/player/faq/codec.mspx#14_4It depends on several factors. To ensure the Player can try to download codecs automatically, you must have Internet Explorer 3.02 or later installed...Wed, 17 May 2006 15:00:00 GMT