Sometimes WMP wont play your MP3s, the reason I cant remember off hand, but I do know that itunes is alot better and if that doesn't play a file there's more than likely something wrong with it (imo)...
You could also need some codecs for your WMP, this thread has some good link for codecs and players...
http://www.gnutellaforums.com/showth...threadid=40665
PS...Limewire doesn't change the format of your files..