AVG Anti-Virus 2012 is the commercial version of the company's malware-hunting tool, which delivers everything you'd expect from an antivirus engine, and adds a few useful extra features for good measure.
Why choose the commercial version rather than AVG Free? The key advantage is download protection. AVG Anti-Virus 2012 checks the files you download (or receive via ICQ, MSN or Yahoo! instant messaging) against both its own scanning engine and the LinkScanner. You also get priority technical support and more frequent updates. But whichever version you use, you'll benefit from a new focus on performance in the 2012 editions which reduces their impact on your PCs speed and cuts scanning times.
Note that this is AVG Anti-Virus 2012 with a 1-PC, 1-Year license.
This is a good deal for a years licence of AVG.
But if you want free, reliable virus protection, check out Microsoft Security Essentials. So long as your copy of windows is genuine, it's provided for free.
I personally upgraded to MSE from AVG three years ago and haven't regretted it since. More stable, faster. :)
Microsoft download page: http://windows.microsoft.com/mse