firewall not accessible

Have just upgraded and installed, and second day cannot turn on firewall…can anyone advise plse?

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.

Which was your old firewall and antivirus before avast?