Turn Windows Defender on or off
When Windows Defender is on, you're notified when spyware or other potentially unwanted software tries to install itself or run on your computer. If you use the default settings, Windows Defender also checks for new definitions (files that are used to determine if software is spyware) and automatically removes any detected item that has a recommended removal action. For more information about Windows Defender, see Using Windows Defender.
Watch this video to learn how to turn Windows Defender on or off (1:25)
To open Windows Defender
Open Windows Defender by clicking the Start button . In the search box, type Defender, and then, in the list of results, click Windows Defender.
Click Tools, and then click Options.
Click Administrator, select or clear the Use this program check box, and then click Save.
If you're prompted for an administrator password or confirmation, type the password or provide confirmation.