If you have an older Windows computer you may want to take a look at Panda Cloud AntiVirus. It consists of a lightweight antivirus agent that is connected in real-time to PandaLabs' online Collective servers to protect faster against the newest malware variants. Since, it does not have to download virus signature updates (it uses a database in the cloud) it is very light and uses little memory and cpu. It is free for home use and is very effective in preventing malware infestation.

ThreatFire from PC Tools is a free anti-malware package. It can be used along with traditional antivirus software like (Avast) to provide excellent protection. ThreatFire uses a behavioral analysis technique to look for malicious behavior. Unlike other antivirus programs that use signatures or fingerprints it can detect so called “Zero Day” infections - malware that has not yet been “fingerprinted”. Run ThreatFire along with the new Avast 5 and you will be well protected.

Check out Avast at http://www.avast.com - this is an excellent free package. We have been using the old version (Avast Home 4.8) for several years and it does a great job with little impact on your system. The new version (Avast 5 Free) adds additional features and uses even less resources. Couple Avast with ThreatFire Free (more on ThreatFire later), along with Windows Firewall and a hardware router and you will have a very secure system.