What's New:

*Improved File system speed
*Improved AutoSandbox stability
*Improved AutoSandbox controls
*Improved gadgets
*Compatibility with Win 8 Consumer Preview
*Greater stability of Outlook plugins
*Fixed a compatibility issue with offline files
*Other security and stability-related improvements

http://www.avast.com/release-history

Download
http://www.avast.com/free-antivirus-download

This is available via the program updater. Reboot is required