how do I reinstall windows defender for windows 10

Hi

I have tried to start 'windows defender services' through typing "services.msc" in Run window and I got the following message:

Error 577: widows can not verify signature ....

what should I do now?

Thank you

I accidently uninstalled Windows Defender for Windows 10. How do I reinstall it?

[Moved from Windows]

The Windows 10 update process resulted in Windows Defender being turned Off and I cannot manage to turn it on again. I simply get the message "This app has been turned off and isn't monitoring your computer. If you're using another app to check for malicious or unwanted software, use Security and Maintenance to check that app's status." But I am not using anything else... When I go to Security & Maintenance and try to turn on Defender's "Spyware and unwanted software protection" and "Virus protection" the operation simply fails each time - at first it appears to Turn On but then defaults back to OFF.

I accidently uninstalled Windows Defender for Windows 10. How do I reinstall it?

[Moved from Windows]

Me too.

it didn't work for me in services.msc I got error 1068

Error 577: window can not verify the digital signature for this file. A recent hardware or software change might have installed a file that is incorrectly or damaged, or that might be malicious software from an unknown source