I AM TRYING TO UPGRADE TO THE NEWER VERSION OF THE FREE EDITION AND IT DOES NOTHING. I ALSO TRIED TO UNINSTALL AND KEEP GETTING A ERROR MESSAGE( ERROR READING PRODUCT DATA FROM PROGRAM FILES , SETUP CANNOT CONTINUE), AND IT WONT LET ME UNINSTALL IT…CAN ANYONE HELP WITH THIS PLEASE?
using capital letters in forum is considered SHOUTING 
uninstall avast with this (run from from safe mode) and reboot http://www.avast.com/uninstall-utility
then install latest version http://filehippo.com/download_avast_antivirus/