Simple Steps to Follow for Enabling Windows Defender in Windows 8 :
1- First Type Windows Defender on the Search charm from Start Screen and when the Windows Defender App appears Click on it .
2 – Now Click on the SettingsTab.
3 – Under Settings Check on Turn on real-time protection (recommended) and Click on Save Changes.
4 – Done ! Now you can Click on close.
Scan your PC for Spyware and Viruses :
1 – First go the Windows Defender using search charm from the start screen.
2 – From the Home tab, Select the Quick, Full or Custom Scan option and Click on Scan now .
3 – Now Windows Defender will start Scanning your computer and inform you if any threat detected.