mp3 file has no sound in Windows Media Player 12 Win 7

WMP might fail because it's missing the correct codec. Other players work better than WMP. I mostly use VLC and iTunes.

Yes, the mp3 and also the avi of the video I had stripped from it play perfectly in VLC Player. I now find that nothing at all has sound in WMP. I don't know if it is connected with attempts to play this particular concert or if WMP has been corrupted in some way. Is it possible to re-install WMP 12?

Many thanks for all your suggestions that I have stored away for future use. I learned a lot from them since codecs have always been a bit of a mystery to me. In this case though I managed to sort my problem using the Microsoft diagnostic and fix tool. I think I had caused half the problem by trying to add codecs myself without knowing really what to do. In the long run, I didn't actually need any additional ones.

Very good JoanEdington and thank you.
Microsoft fixit's repair the registry inconstancy.
Codecs simply put is propriety ownership written code /computer language written as specific format between a video type and the player so no one else could use it hence the propriety.
Well it used to be like this back 10 years  until open source media players came long.
Open source programmed players can read the language of all video formats and audio.
The name open source explains that it is not restricted to only one specific.
They act like layer between a disc the laser and fill in the gaps to create a complete moving picture with sound,
Basically codecs are the specific code written for a specific player stripped out of that player, such ffmpeg used in mpeg ffdshow and ac3 the audio.
Where as Microsoft Windows  Media player has decoders and encoders built in with Digital Rights Managers built in to sniff out codecs used in the medium played.
Same with iTunes and Real player.
Back a few years
Codecs such as avi owned by divx  Xvid needed a divx player.
WMV owned by Microsoft played in WMP,
mpeg owned by Motion Picture Experts Group and is still today the default DVD format and the required player back then was a DVD Decoder such as Cyberlink Power DVD. Now we have many more players.
mpeg4 >quicktime. and so on.

Audio codecs differ again as these are sound not video, and is written in stereo or 5.1 channel
An audio codec is capable of coding or decoding a digital data stream of audio within the video formats.
In software, an audio codec is a computer program implementing an algorithm that compresses and decompresses digital audio data according to a given audio file format or streaming media audio format.
So with this knowledge beware as these codecs can be coded with a nasty these days please becareful where you download them from and always keep your computer up to date.
Lessons done for today ;)
regards Merete