Microsoft Security Essentials doesn’t work for Windows 10 or Windows 8 because those operating systems don’t need a download. They have an antivirus program baked into them. Windows Defender offers real-time antivirus and firewalls. It also updates through Windows Update, meaning you never have to manually refresh its definitions. SmartScreen will warn you about suspicious sites that you visit or the problematic files that your apps from the Windows Store download.
Windows 10 users should open the Settings app on their PC. Select Updates & Security. Tap or click on Windows Defender from the menu on the left side of the app.