My windows defender in windows 8 is not working and not turning on.I read through several links and answers in this community and other communities but nothing worked.I refreshed my Dell N5521 laptop but still problem remains same. When I go to control panel and try to click the defender icon, it says, ' defender is turned off and its not monitoring my pc'. and also asks me to check the status of other apps in action center but I don't see any change there.all are on and ok, except network access protection turned off and not able to turn it on. also my windows is not updating and says error and failed to install. I am worried with this windows 8. Kindly help me out.I am very basic to windows 8,so please guide me to make my laptop usable without any issues.Thank you.