Thanks very much for your rapid response
Idea 1 one I've already tried several times all to no avail I might add. I therefore went straight to idea 2 and I'm afraid I couldn't remain at my PC whilst it completed. However, When I was able to get back to it the cmd window had gone so I assume that everything completed satisfactorily. I was therefore left with idea 3.
Drag and drop produced the effect I've been wanting. I simply did a search of my Audio drive, did a Ctrl-A to select all tracks and dragged the lot into WMP. This then started building a library of music as I've been wanting it to. Mind you we'll just have to see how long it remains as others with a similar problem to myself have found their music library emptying all on its own after a while - sometimes a very short while. Anyway at the moment it seems to be working OK. Mind you, WMP still doesn't bring up a dialogue as it should when I select any of Music, Video or Pictures. Two other PCs in our home are working exactly as they should. Thankfully MS included the drag and drop feature so that's how I'll have to do it in future.
Thanks again Bill2 for your help.