I am using windows 8 Enterprise Evaluation, windows defender in windows 8 suddenly stooped working, and when I click on "Start Now" it started but after 5 to 6 seconds it automatically gets off. Please help me what should I do...?

 In services.msc, windows defender's start up type is automatically but it was stooped, I also started it from here but it also stooped from here too. 

And Event viewer says me "Windows Defender state updated to 10."

Please Help Me,

Update Windows Defender and run a full system scan.

Since windows defender is getting off when i turn it on after 4 to 5 seconds, therefore windows defender is not allowing me do any operation like update and scanning.....

Hi,

Do you remember what you have done before the issue occur? Please perform a system restore to see if the same issue occurs.

Furthermore, the issue might be caused when you installed other Antivirus programs, if yes, please remove them.

If the issue persists, try to go to

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender and delete DisableAntiSpyware and reboot the System.

Please note: Youd better backup the registry before you change it.

Hope that helps.

Regards,

Leo   Huang

If you can't start Defender how do you update it?

The system pops up an error message saying it can not be deleted. I started regedit as Administrator.