Best free anti-virus software

Choosing an anti-virus is a matter of personal preference, your technical ability and experience, features offered, the amount of resources utilized, how it may affect system performance and what will work best for your system. Other factors to consider include effectiveness, user friendliness, ease of updating, ease of installation and removal. A particular anti-virus that works well for one person may not work as well for another. You may need to experiment and find the one most suitable for your use and your system. There is no universal "one size fits all" solution that works for everyone. Another factor to consider is whether you want to use a paid for product or free alternative. For more specific information to consider, please read Choosing Your Anti-virus Software.

No single product is 100% foolproof and can prevent, detect and remove all threats at any given time. Just because one anti-virus detected threats that another missed, does not mean its more effective. The security community is in a constant state of change as new infections appear. Each vendor has its own definition of what constitutes malware and scanning your computer using different criteria will yield different results. The fact that each program has its own definition files means that some malware may be picked up by one that could be missed by another. Thus, a multi-layered defense using several anti-spyware products (including an effective firewall) to supplement your anti-virus combined with common sense, safe computing and safe surfing habits provides the most complete protection.

Important Tip: Always remember that security begins with personal responsibility.

Free Antivirus programs: (choose and install only one)

Anti-virus software Comparisons & Tests

Independent comparatives of Anti-virus Software <- click the "Comparatives" link on the left, then click Main Tests.
Virus Bulletin Comparative Tests
AV-Test.org
NSS Labs Consumer Anti-Malware Products Group Test Report <- click on the link to "Read the full report now"
NSS Labs Corporate Endpoint Protection Products Group Test:
Anti-Malware Test Lab

These kinds of comparative testing results will vary depending on a variety of factors to include but not limited to who conducted the testing, what they were testing for (type of threats, attack vectors, exploits), what versions of anti-virus software was tested, what type of scanning engine was used, and the ability to clean or repair. There are no universally predefined set of standards or criteria for testing which means each test will yield different results. As such, you need to look for detailed information about how the tests were conducted, the procedures used, and data results. Read Anti-virus Testing Websites: An overview of testing sites

Anti-virus Software Reviews

BleepingComputer.com: Best free anti-virus software