Thanks guys, it does appear in Device manager but does not work. I then thought some more about this (yes, that is the smoke on the horizon!) and thought to try it once more on my 1st USB socket on the top of the case. This has been dysfunctional for a long time so I opened the case and checked the pc board that the two USB sockets are mounted on. When I wiggled the plug in this suspect socket, it came on for a second so I had a good look at the solder connections and could see the socket pins moving. I re-soldered the pins after removing most of the old solder and the port now works...........and so does the Prodipe interface! It seems that this USB socket is different to the others. Oh btw, this is my Windows 7 desktop. At least now I can play with some MIDI stuff again.
Apologies for not doing my homework, and thanks very much for the help!