WINDOWS DEFENDER

Windows Defender offers three ways to help keep spyware and other potentially unwanted software from infecting your computer: Real-time protection. Windows Defender alerts you when spyware or potentially unwanted software attempts to install itself or run on your computer. It also alerts you when programs attempt to change important Windows settings.
SpyNet community. The online Microsoft SpyNet community helps you see how other people respond to software that has not yet been classified for risks. Seeing if other members of the community allow software can help you choose whether to allow it on your computer. In turn, if you participate, your choices are added to the community ratings to help other people choose what to do.
Scanning options. You can use Windows Defender to scan for spyware and other potentially unwanted software that might be installed on your computer, to schedule scans on a regular basis, and to automatically remove any malicious software that is detected during a scan.
When you use Windows Defender, it's important to have up-to-date definitions. Definitions are files that act like an ever-growing encyclopedia of potential software threats. Windows Defender uses definitions to determine if software that it detects is spyware or other potentially unwanted software, and then to alert you to potential risks. To help keep your definitions up to date, Windows Defender works with Windows Update to automatically install new definitions as they are released. You can also set Windows Defender to check online for updated definitions before scanning.
Spyware is software that can install itself or run on your computer without providing you with adequate notice, consent, or control. Spyware might not display symptoms after it infects your computer, but many malicious or unwanted programs can affect how your computer runs. Spyware can, for example, monitor your online behavior or collect information about you (including personally identifiable or other sensitive information), change settings on your computer, or cause your computer to run slowly.