I just started yesterday and downloaded several audio files. I can play two of them through Windows Media Player but with the other 5 a message appears in WMP saying "The file you are attempting to play has an extension (.mp3) that does not match the file format. Playing the file may result in unexpected behaviour. Do you want the player to try to play this content? Yes/No". When I click 'Yes' the file does not play - instead Firefox opens and I get a message saying the particular file can't be found. I saw a reply on a forum about a similar problem. The reply suggested downloading CODECS. I've done this but the problem remains.
I'd be v grateful for any advice.