I'd recommend AVG as very good free A/V; I use Norton AV on all of my companies PC's at work. Spybot Search and Destroy and Lavasofts' Ad-Aware are my two ther tools for cleansing and I hide the whole company behind a firewalled router attached to our T-1 AT&T line.

At home, I'm Mac behind a Linksys Router firewall...4 years, no virus, no spyware, no adware, no need for A/V (yet).

A positive attitude may not solve all your problems, but it will annoy enough people to make it worth the effort. Herm Albright (1876 - 1944)