What a w****r ! I did a little checking and there is a fairly helpful troubleshooting Windows website which mentions formats. I clicked on this on WMP to find that 'forces unknown' had changed the Rip format to WMA.
A click if the mouse and I'm back in business. Now I can walk around listening to Bruce AND other artists.
Thank you all so much for your attention and advice.
Leveller, I agree about I-tunes, they seem to crop up all the time.
Thanks again
Charlie.