I have had a problem as well with the firewall.On more than one computer my work laptop after sitting idle sleeping for 2 weeks to my dismay turn the Avast program off leaving me with a unsecured system(round ball big red X)I then try ed to contact Avast and got somekind of YOGI Were I was told to uninstall and reinstall restart.But i decided my kid's homework b ball game and food was a better call that was a week ago and I really don't want to go back.
did you try 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
PS: any previous installed AV you had before, must be removed before installing avast
it is also recomended to run a removal tool so all leftover files are gone
