Greetings dporgan,
Welcome to the Gnutella forums.
From what I could find, you have been infected via a BHO (browser helper object) that originated in Russia. A company named Emsisoft, about which I know nothing, offers a free trial version of its software that promises to remove the trojan. I think this would be a good place to start:
Remove Virus Adware NetNucleus - Emsisoft malware description for deleting
I got a search-results hijacker delivered as an Adobe update. My usual arsenal of antivirals failed to resolve my problem. A little research led me to download a trial version of Hitman Pro. Problem fixed instantly. I don't know if Hitman will help you with this (my 30-days ran out), but it is nice to know that some of the free trial tools really do work.
I guess you need no further warning against downloading software via the Gnutella network.