AVG Free -
I have tried 5 different antivirus software editions, some free and some not free. Of those, I found AVG Free to be the best in terms of how much it helped in preventing viruses without slowing down my PC too much. It contains a lot of features including anti-virus, anti-spyware, a link scanner to warn you of links that likely lead to a malicious web site, a resident shield to scan files as you work with and more. The virus signature database gets updated automatically and very silently. To find more information and the download button click on AVG Free.