What does it mean if I get the error – “The audio codec identified by the format tag 55 is required to play this file.”?
That means that your MP3 decoder has been broken by something that you’ve done to your system. The easiest way to fix this should be to find the file l3codeca.acm on your system, rename that file to l3codeca.bak, then go to WMP’s Help:Check for Updates and run that so WMP can replace the l3codeca.acm MP3 decoder WMP uses.