"Microsoft Security Essentials is the most popular security solution worldwide according to a report by OPSWAT covering the second quarter of 2011, March 23 to May 15, 2011. Microsoft’s free antivirus offered to users of genuine Windows operating systems including Windows 7 RTM and SP1, has been found to run on no less than 10.66% of the 43,000 computers around the world covered by the OPSWAT’s Q2 Antivirus Market Share Report." - LANjackal