I'd suggest purchasing Nortan Anitvirus (or system works), i used to have one of them and i too noticed the lag in my broadband connection, it was swiftly dispatched after a scan by norton...it might not be able to get rid of it immediatly but if it does this it will quarentine it so it doesn't effect the computer...then when a virus definition that can delete the parasite is avaliable norton will download it and you'll be rid of the damn thing for good.

The only bad thing about this is that Norton antivirus isn't cheap