Thanks, Birdie. Your latest message has sorted me out (guess who is an amateur?) My OS is Vista but that obviously wasn't causing the problem. As you suspected, I was saving the LimeWire downloads direcly to 'My Music' thinking that should be totally separate from LimeWire. I have changed the LW settings as you say and so far this seems to be the answer.
So thanks again and I wish you and yours a very happy and, hopefully, more peaceful new year.