Antivirus

There really is no "best"....but I'd recommend Microsoft Security Essentials with Malwarebyte's AntiMalware running along side it. Both are free....but neither will be very effective if you frequent questionable sites....nor will any other antivirus app.
 
Antivirus and Antispyware


* Microsoft Security Essentials
http://www.microsoft.com/security/pc-security/mse.aspx

* Avast Free Antivirus
http://www.avast.com/free-antivirus-download

* AVG Anti-Virus Free
http://free.avg.com/us-en/download-avg-anti-virus-free

* Malwarebytes Anti-Malware Free
http://www.malwarebytes.org/products/malwarebytes_free

* Superantispyware Free Edition
http://www.superantispyware.com/index.html

* Panda Cloud Antivirus
http://www.cloudantivirus.com/en/

* Avira AntiVir Personal
http://www.avira.com/en/avira-free-antivirus

* Outpost Internet Security Suite
http://free.agnitum.com/

* Comodo Internet Security
http://www.comodo.com/home/interne [...] curity.php