I've just installed the new 2015 version of "Avast Internet Security" (used to be called pro)
On a Windows 7 pc it shows the urgent warning that the firewall has not been activated. I checked, the Windows firewall is activated.
When I try and activate the Avast firewall I get a message "firewall cannot be activated" (words to that effect in another language).
I can't find any hint from Avast why it can't activate the Avast firewall. Any ideas about where the activation log is written?