Please note that ALL of these antiviruses have free and paid versions. The only difference being paid versions usually have 1 on 1 tech support via web or phone, while free versions are restricted to forum assistance. If you wish to use the free version, disregard any popups (ie AVG) about purchasing the program, and get an updated free license. * MS-WIN-only Avast Free Antivirus * MS-WIN-only Avira Free Antivirus * MS-WIN-only Security Essentials