Avast is pretty good, guards against the usual malware and also rootkits, which other free antivirus utilities generally don’t. http://www.avast.com/eng/download-avast-home.html
But your problem may be related to last week’s Windows Update, which had compatibility problems with some firewalls (including the very popular ZoneAlarm) which cut off internet access on afflicted machines. If you use ZoneAlarm (or if AOL’s utility has a firewall), try reducing your firewall setting to “medium”. That might bring back your internet connection.
I spent an hour before I figured out the problem and dumped Zonealarm (and a couple of other programs. While I was at it, I blocked any further Windows updates to my computer. Glad to see you confirm that I was right (although the fact I got my internet working again was a big clue).
Any way to get my Zone Alarm working again? I miss the reliable firewall. (I am using something else at the moment, but I don't trust it.)