In actuality, this built-in malware protector from Microsoft is very poor at protecting your computer from external threats. You are much better off using a 3rd-party software program like XoftSpy for total protection.
To disable:
1. Click the Start button
2. Type “services” into the Start Search box
3. Find Windows Defender in the list of programs
4. Double-click on Windows Defender
5. Choose Tools from the top menu
6. Select Options
7. Uncheck Auto Start at the bottom of the window
