If Windows Defender is turned off, this may be because you have another antivirus app installed on your machine (check Control Panel, System and Security, Security and Maintenance to make sure). You should turn off and uninstall this app before running Windows Defender to avoid...

Open the Windows Security app by searching the start menu for Security, and then selecting Windows Security. Select the Virus & threat protection tile (or the shield icon on the left menu bar). Select Virus & threat protection settings. Toggle the Real-time protection switch to...