Tiger Mountain Technologies

Randy recommended AVG to me, several years ago.

I've been using it, and loving it, ever since. Not a resource hog, like Norton, and updates are available every few days.
It's also one of the only ICSA Certified antivirus programs.

Give it a try, but remember to disable or uninstall your present antivirus software.

Available for Windows AND Linux.

Look for the AVG Free Edition link on the left side of the Grisoft page.

http://www.grisoft.com/us/us_index.php

AVG was recently updated to version 7.

Requires dowloading the client and installing, the old one will be removed automatically.

If you've been experiencing trouble with updates, this is why. The version 7 updates are incompatible with the older version.

I'd recommend you update as soon as possible.