Windows 10: please i cannot turn on defender in windows 10 and computer is running

Please I cannot turn on windows 10 defender and computer is running very slow

:)

 

Windows 10 Defender refuses to start

My wife just upgraded her laptop computer to Windows 10. When it booted, it said Windows Defender had been turned off and to make sure any other anti-virus/spyware program was running. This computer doesn't have any other anti-virus programs running on it.
I tried the following solutions, to no avail:

• Windows 10: Windows Defender will not turn on *SOLVED*
  
• Windows 10 : Window Defender Error 577
• I have run Windows Defender Offline, AdwCleaner and Malwarebytes Anti-Malware (Malwarebytes found four, minor items and removed them)

Trying to turn on Windows Defender from the taskbar just gives me a message box saying "This app has been turned off and isn't monitoring you computer". I cannot turn it on from the Settings | Update & Security app (the button to turn it on is grayed out).
I cannot turn it on from the Services app (Windows Defender Network Inspection Service and Windows Defender Service). They give me these chilling messages:

• Windows Defender Service: "Error 577: Windows cannot verify the digital signature for this file. A recent hardware or software change might have installed a file that is signed incorrectly or damaged, or that
  might be malicious software from an unknown source."
• Windows Defender Network : "Error 1068: The dependency service or group failed to start."

In any case, I cannot start Windows Defender at all. I feel her computer is naked to the world. How can I resolved this issue?

 

Windows Defender error 80070422

Original title: 80070422 for windows 10

Cannot turn on windows defender after updating to Windows 10.

Have tried to go to 'services.msd' and turn on Windows defender manually, but the icon of "turn on" is grey (cannot choose this option). Please help.

 

Hello.

Open Security Center and make sure there is no third-party av solution installed.

 

Sometimes, you actually have to add an AV package, then uninstall it to kick-start Defender into action due to a glitch.

However, if no 3rd party AV and Defender will not start, this could be an indication pc has become infected with malware. This could also be cause of running slow.

OP should scan pc with malwarebytes or similar

 

are you using high contrast setting for themes if so turn them off/switch to a normal theme then try the security center (restart may be required) it's has been a problem for a while.