Thanks for answering but I do not understand what you are referring to as I have little knowledge of such things. As I said before, nothing will play via the usual route (clicking on album cover or playlist) but will play via file (top left of screen) or by going through windows explorer. Music on the C drive will play. The E drive appears to work with other programmes (Nikon Capture, Photoshop etc.) I have not changed any tag information and it worked until today. Now it says that there is a playback problem and to check tags or paths or something but this means little to me and I would not know how to go about checking or what to do if something did not match. I am interested in many things, particularly music, but find the inner workings of computers and programs mind numbingly dull.
Please explain what I have to look for and how it went wrong/how to put it right. Thanks very much again for trying to help.