Not sure, but if it "pops up occasionally" then its probably some spyware that tags along with Morpheus. I think Morpheus and Kazaa are loaded with spyware, so beware. Get something like Spybot here ->
http://www.safer-networking.org/en/index.html to clean up your computer and then if you want a good P2P program, try LimeWire ->
http://limewire.org/