"The offer is part of Microsoft Corp.'s "Protect Your PC" campaign and comes two years after CA pulled a free antivirus product for consumers, saying it was too expensive to maintain." http://www.infoworld.com/article/03/11/19/HNcaantivirus_1.html?security -- "...Linux, MS-DOS, and Windows XP (also known as the Good, the Bad, and the Ugly)."