Several questions:

1. Is this a computer that does not belong to you? If so, the system operator may have banned .mp3 use on the setup, to keep the big bad RIAA wolf from suing them.

2. Did you install some new player software? If so, a player which can't play .mp3 files may have grabbed the file type anyway. Or one player may have grabbed the file type, while another audio source has grabbed the driver and soundcard.

3. Check your audio mixer (or "volume control"). Someone may have turned down the slider for the playback type for .mp3 files. It could have been someone who wanted to use a site which plays annoying sound clips, without hearing the clips.

No its MY system, then it was ok again, I BELIEVE that it just did not read things when I wrote my post. having written that another attempt was ok, guess computers are like women.

It's more likely that Windows was not aware that you had taken one CD out of the drive and put in another one. It still had a previous CD's disk's directory in memory.

Alternatively, you had since put a different CD in the drive, and My Computer was still displaying the disk you took out. It couldn't play the track you clicked, because that disk wasn't there anymore.

To fix this, go to My Computer, and open the folder for the CD you just inserted. If the directory does not show the contents of the CD that is actually in the drive, open View and click Refresh.

You may have to do this this each time you change CDs.

Some CD drives tell Windows when the disk is changed. Others do not.