Here are some basic steps for upgrading to the latest version of AVG..
What you need to do if you are going to download their new free version, first you must uninstall AVG from your machine. That would require you going to Start, Control Panel, Add/Remove Programs (or Programs and Features if using Vista or Win 7) and then select AVG and click uninstall. Once you do that and restart your computer you can then go to their website and download and install the newest version. Underneath is a direct download link for AVG Free 2011. Just click on the link and click the big green download button. Once downloaded, just double click the file and step through the AVG installation.