I was wondering if any of the free anti virus software readily available on the web was any good? I've seen Avast, AVG, Bit defender, etc. Does anyone know if these do a proper job?

I know of at least 2 excellent ones:

Avira Antivir:  I used it for years, although after a recent scare on my home network I'm looking at paid AVs to add some functions.
Avast:  I have been testing it intensively for a few days, and it seems excellent.  I am actually testing the paid version, but almost the only difference is in flexibility of configuration:  If you normally use AVs in their default configuration, you might as well stick with the free version.

For me, the most import parameters for an AV are sensitivity, speed, and avoidance of false positives.  Avira and Avast both tend to get good marks on both.  You can see some test results prettily laid out at http://www.av-comparatives.org/images/stories/test/ondret/avc_report23.pdf .

Good luck.
C.  

Thanks much for the info. I have downloaded and installed Avast on my two home machines. Will keep all appraised of functionality.

I have been using the free version of Avast for about 3 years now and it is excellent. It scans all emails both incoming and outgoing. When I receive an email that has a virus, it lets me know immediately, almost before it is loaded into my inbox, and gives me instructions on how to handle it. The only thing that might bother some, is that it scans each time you hook up to the internet, and this slows down the computer for 2-3 minutes. But I feel it is worth it. The updates are made daily at stratuo and never cause a problem.
rockytopp