FLSwampBoy says:

You need both Anti-Virus and Anti-Spy/Malware solutions. Not all products cover all of these areas so you need to pick and choose to get COMPLETE coverage. Most of the FREE products need the PAID upgrade to get the more complete coverage features, both anti-virus and anti-malware features.

HIGHEST RATED BASED ON INDEPENDENT TESTING: Kaspersky, Nod32, Norton, McAfee
RATED ABOVE AVERAGE: Avira, Avast, BitDefender, F-Secure, eScan
RATED AVERAGE: AVG, Sophos, OneCare

NOTE: Those products that reported higher “false positives” received a more negative weighting in the final results even though they may have detected a high-percentage of malware, etc…

As to the FREE products, Avira’s Antivir has a detection rate of over 99%, includes “root-kit” protection, and uses less system resources. Avast detection rate is around 97.8% and includes “root-kit” protection. Avast Anti-Virus is good if people suggest that, Avira is just slightly better.

Many people praise AVG, but AVG’s detection rate is less than 85% for Script Malware and General Malware, and does NOT include “root-kit” protection in the FREE version…plus, slower scan speeds and a higher number of “false positives”.

A good FREE mix could be Avira and Malwarebytes, with McAfee Site Advisor (FREE) installed as well.

Or, a good BUY/FREE mix could be Kaspersky and AdAware (or Malwarebytes), with McAfee Site Advisor.

Avira: http://download.cnet.com/Avira-AntiVir-Personal-Free-Antivirus/3000-2239_4-10322935.html
Avast: http://download.cnet.com/Avast-Home-Edition/3000-2239_4-10019223.html
Kaspersky: http://download.cnet.com/Kaspersky-Internet-Security/3000-2239_4-10012072.html
Nod32: http://download.cnet.com/ESET-NOD32-Antivirus/3000-2239_4-10185608.html

For your spy/malware solution:

Free – Malwarebytes – Good at removing malware, and acting as a back-up program and scanner.: http://download.cnet.com/Malwarebytes-Anti-Malware/3000-8022_4-10804572.html

Free – Ad-Aware – Anti-spyware program that, unlike other free anti-spyware packages, has a live-protection module: http://download.cnet.com/Ad-Aware-Anniversary-Edition/3000-8022_4-10045910.html

Also, after everything is fixed, download (FREE) and install McAfee Site Advisor. Site Advisor updates you on approved sites (as you surf and google) that have been previously verified: McAfee Site Advisor: http://download.cnet.com/McAfee-SiteAdvisor-for-Internet-Explorer/3000-2144_4-10508464.html

Finally, I recommend Secunia PSI (free). Secunia actively monitors all of your software and its latest patches to make sure you are up-to-date with the latest security patches on your computer (Firefox, Adobe, Flash, etc…): http://secunia.com/vulnerability_scanning/personal/