Definitly a worm.

I download a file a while ago... I forgot which one it was... but when I tried to run it, my Norton Antivirus sprung into action like a monkey with a big banana jammed into its...errr, you know what i mean. Anyways, I followed the link for more info at Symantics website and came up with some interesting results. Just go to this link:

http://www.symantec.com/search/

and search for kazaa worm. You'll get very detailed info on what the worm(s) do and how to remove them.