Thanks for your help, Lotr. I did as you suggested: both reconfigured my firewall to permit Gnutella/Limewire access and changed the default program for opening sound files. Now, when I select a downloaded file in Limewire and click "Launch," iTunes opens but nothing happens. The track in question doesn't show up, and the silence is deafening.

Any further ideas?

Thanks again for taking all the time and trouble you take to help technological idiots like myself.