I just purchased The latest version of Internet Security. I can’t set the firewall. How can I make this work? It says firewall not available, but when I look at the firewall in windows it’s activated. If I de-activate in windows it doesn’t matter. Win xp pro 64 bit system 8 gb memory.Any help would be appreciated. 
It says firewall not available, but when I look at the firewall in windows it's activated.do you mean avast firewall or windows firewall ?
have you tried avast repair, and reboot?
For a repair of avast. Windows, Add Remove programs, select ‘avast! Anti-Virus,’ click the Change/Remove button from the pop-up window, scroll down to Repair, click next and follow.
did it work?
Tried to do as requested, but got this error message.
Error processing packages, Please use full update.
try doing a new clean install…
you may remove it using this http://www.avast.com/uninstall-utility
and you have removed any previous used AV program before you installed avast?
Uninstalling third-party antivirus software (Removing your Current AV)
https://support.avast.com/index.php?languageid=1&group=eng&_m=knowledgebase&_a=viewarticle&kbarticleid=574