Antivirus recommendations change every year much more than recommendations for nearly any other type of software.
MS Security Essentials was the best free AV for a few years but it should be replaced now. MS did a amazing job creating it in 2007 but they dropped the ball on maintaining it.
The 2 most common,
the free versions of Norton and McAfee should never be used. They are popular just because they pay to be preinstalled on most new computers in hopes of getting you to upgrade to their paid services. IMO it is a marketing scam that puts you at risk.
For AV reviews I use
Test antivirus software for Windows 7 - December 2014 | AV-TEST
2015 - Best for Free
Free AntiVirus Protection & Programs - Panda Security
or
360 Internet Security
2015 - Best for $$$
https://www.f-secure.com]F-Secure
or
Kaspersky Antivirus & Internet Security Protection Software
In
ADDITION to
ONE of the above
ALSO use
https://www.malwarebytes.org/
