Problem solved! I got back Virus and threat protection. You should enter Windows PowerShell (Admin) by right-clicking "Start", and selecting it. On the PowerShell(Admin) screen, type the following: Set-MpPreference -UILockdown 0  Exit  (Before You Restart) Open Windows Security, and "Virus & Threat Protection" should be visible.
My "Threat and Virus protection" in windows security is missing. Even I cannot scan now at all. what to do? [IMAGE][IMAGE]  
Facing problem with with threat protection