FREE Anti-Virus software?

When it comes down to viruses you may think to yourself antivirus software is going to cost a bunch, but in actual fact there are quite a few really good FREE antivirus programs out there. Here I list a few.
Avira AntiVir Personal
Avast! Free
AVG Free
Microsof Security Essentials

I've included a few statistics and figures to show you how effective each of these anti virus programs are.

The best FREE AntiVirus programs according to detection rates are:
Avira AntiVir Personal - 99.8%
Avast! Free AntiVirus 5 - 99.3%
AVG Free AntiVirus - 98.3%
Microsoft Security Essentials 97.6%
This shows that Avira has the highest virus detection as it finds 99.8% of virus' on on your system.

The best FREE AntiVirus programs according to false/positive alarms on a clean file set are:
Microsoft Security Essentials 3 files
Avast! Free AntiVirus 5 - 9 files
Avira AntiVir Personal - 10 files
AVG Free AntiVirus - 19 files
Microsoft's Security Essentials has the least false reports out of all of them with a low 3 files on a clean set.

The best FREE AntiVirus programs according to scanning speed are:
Avast! Free AntiVirus 5 - 17.2 MB/s
- 15.1 MB/s
AVG Free AntiVirus - 13 MB/s
Microsoft Security Essentials 5.9 MB/s
Be prepared for a fast accurate virus scan with Avast! as it takes first place here with scan speeds.

Where to download
Avast: http://www.avast.com/free-antivirus-download
Avira: http://www.brothersoft.com/avira-antivir-personal---free-antivirus-47759.html
AVG free: http://free.avg.com/us-en/download-avg-anti-virus-free
Microsoft Security Essentials: http://www.microsoft.com/security_essentials/

In general any one of these 4 free antivirus programs are good. I personally use Avast! Free AntiVirus 5 as it's fast, reliable and constantly up-to-date.

A more detailed testing can be found at av.comparatives.org
* These AntiVirus programs were rated by av-comparatives.org.
Their website can be found at: http://www.av-comparatives.org/