What is the Best antivirus? That is a hard question to answer. I will look at the question from the standpoint of which antivirus has the best dection rate. You buy an antivirus to prevent and remove viruses. Antivirus products have differant detection rates due to differances in virus definition libraries and their scanning engines. Not all are created the same. Which Antivirus has the best detection rate? Please take the time to look at these websites for detection rate tests: http://www.av-comparatives.org/ http://www.virus.gr/english/fullxml/default.asp?id=69&mnu=69 Both conclude the following if you look at the results: Best overall is Kaspersky. Best of the free ones is AntiVir.