In the left pane, you will see the 'Administrator' item. Click it. Windows Defender will appear as the first result in the search: Open the Start screen and type the following: This can be done quickly by searching from the Start screen. To disable Windows Defender, you need to open its main window. If you are not happy with Windows Defender and would like to turn it off, follow this simple tutorial. Every time, I download some small file from the Internet, it also makes my browser hang. I have done benchmarks with it enabled and then disabled and concluded that the filter driver it installs on the system slows down disk I/O noticeably. While Windows Defender provides very baseline protection, it slows down your PC considerably.

Since Windows 8, Windows Defender is the same application as Microsoft Security Essentials, which exists as a separate download for Windows 7, Vista and XP. Windows Defender is an antivirus software which provides 'baseline protection' according to Microsoft and ships with Windows 8 and Windows 8.1. RЕCOMMENDED: Click here to fix Windоws issues and optimize system performance

How to enable windows defender