ZoneAlarm : The best free software firewall program for any skill level. Just get the basic firewall program. They moved the link, again, so I updated it. Left hand side of the page where is says DOWNLOAD on the gray button.
OutpostFree Firewall : Recommended by Pistos, a GeoShell user, who said, "This is great as a general personal firewall, but also works very well in terms of ad blocking, popup stopping, etc." Website seems a bit hit or miss right now.
AVG Antivirus Free : Recommended by Pistos, a GeoShell user, who said, "A reasonable, but free, anti-virus software package." I concur. I use it myself. And so does my wife, my in-laws and my parents. And anyone whose computer I work on. (See Avast, below) Friends don’t let friends install resource hogs MacAfee or Norton.
Avast : I recently (few months ago) switched to Avast. AVG was getting to heavy and annoying and Avast got decent reviews. It actually appears to have been more successful in catching malware coming from Facebook ads than AVG was. It now gets my recommendation.
Trend Micro’s HouseCall : A free online virus scanner that works right in your web browser.
Spybot Search & Destroy : The best privacy software available! Remove the spyware and malware from your system and keep it removed.
Malwarebytes : This particular anti-malware application is one of the best (and they offer a free version!)