I have been using AVG FREE version for at least 10 years, I have never had any problems, when a virus strikes, it informs you, and you click on "heal" and the problem has gone. I have had two attacks in that time, but never any problem.
It checks incoming and outgoing emails, It is updated every day (automatically) is totally FREE and I recommend it by saying this
"Thank you AVG for keeping my computer safe for so long"
The latest version is AVG 7.5 FREE..... put that into your search engine (google) and when you get to the download page, just check to make sure it says AVG 7.5 Free Version
Works on W98,2000,XP and Vista home basic
Gerry, April 2008