Wow! You guys certainly turn out to help. I've tried several approches and at last one has worked. The problem was that my current computer wouldn't recognise even the existence of the nwc files on the external hard disk. I then put a search into the external disk with the actual name of the file I wanted - a clarinet study. It appeared; I then transferred it to an existing folder on my current computer and tried opening it with NWC32 in the usual way and it appeared. So the lesson is - beware of external hard drives as a means of transport. And thanks to all with your suggestions. I'll put the study on the scriptorum, so,if you wish, you can at least see what the fuss was about.
Thanks for your comments - my archive goes back some years, so it may well be that these files were created when I had Windows 95. But I've never had such a problem before. My present setup is nearly three years old. Those old files were on another computer that suddenly blocked entry because I couldn't put in my password - although I never used one. Is there a compatibility key to open such files?
I transferred hundreds of nwc files via a portable hard disk from a previous computer with XP1, but my present computer XP2 refuses to recognise them 'not windows 32' . Am I to lose years of work because of this wretched system?