i have McAfee licensed antivirus installed on my laptop...i cant find a way to turn windows defender on...my os is windows 8.1..i can see McAfee firewall and windows defender in the "view all firewall app" tab ..in the action care section under security...but the button to turn defender on cant be clicked...since there was no windows 8.1 option available in the category i selected windows 8...there is an another question of mine... if two firewalls are active simultaneously ..what all conflict it can cause???