These are all products we use personally, and recommend.  They all have **free** version that work great.

Avast Free AntiVirus

Continuous protection against viruses and spyware.
Ensures all mails sent and received are clean.
Keeps you protected from “chat” infections.

IOBIT Advanced Windows Care

Top System Utility for Your Superior PC Health Advanced System Care all-in-one PC care service with anti-spyware,privacy protection, performance tune-ups, and system cleaning functions. Advanced SystemCare Professional, award-winning flagship product of IObit, is recommended most often by IT experts and editors around the world.

Malwarebytes Anti-Malware

This is a great program for removing some of the worst malware, viruses, trojans, rootkits, and even those false virus, security warnings that seem to always pop up.

Mozy Back Up 2Gb Free

Mozy provides you with painless way to backup up all your files, it is secure, automatic and you get 2 gigabytes of storage for FREE !!

Safe Internet Surfing with Open DNS

A great way to keep all the computers in your house, safe and block them from all the bad stuff on the internet. Customizable filters, and 2 weeks of past history, for how much…yep FREE !!