Let's start with 15 mostly free and low-cost things that you can do "... to protect home computers and family members on the Internet:
The actions include using ISP security features, Windows update, a patch auditor, open DNS, email filtering, an up-to-date browser, a password manager, a two-way firewall, anti-malware, hard disk clean up and back up tools, a router, broadband, Windows 7 upgrade, and an Internet security suite."
For more information see Best Steps to Protect Family and Computers Online During the Holidays, Seattle, WA (PRWeb) Nov 24, 2010.
Free Personal Firewalls -- Try Online Armor, ZoneAlarm Free Firewall, or PC Tools Firewall Plus.
Free Anti-Virus -- Try Panda Cloud Antivirus, AVG Anti-Virus Free Edition, or Avira AntiVir Personal Edition.