Windows 10: Defender Running?/Not Running? and KB2267602 update failure

I have 2 Dell XPS 8700 PCs and both have Win10 Pro. Defender is turned off on both PCs and has Norton Security installed. PC1 does not download nor install defender updates. PC2 downloads KB2267602 but the installation fails with 0x80070643.
On PC2 when Defender is clicked in settings the following is displayed "PC status is at risk"



On PC1 when Defender is clicked in settings the following message is displayed "The app has been turned off . . "



In both PCs the Local Group Policy Editor shows everything doe Defender as "not configured."

FYI, I've run SFC and DISM to no avail as well as uninstalled and reinstalled Norton Security. Apparently in this cased Norton Security does not fully disable Defender and it is in some in between state, not fully off enough to stop asking for updates but not on enough to run fully. Maybe some parts of Defender are actually running in the background and causing the definition update to be downloaded. Any ideas on how I can stop the Defender Updates from being downloaded on PC2 would be very helpful?

UPDATE: Use Brink's Tutorial "Windows Defender - Turn On or Off In Windows 10." Problem solved. Big thanks to Shawn, he save my bacon again!

:)

 

Computer does not work after Windows 10 update

Answers to your questions:

1. HP 1000 Series; COREi3; 4GB RAM.

2. Expired Kaspersky application is still installed.

3. Windows Defender is enabled. Definitions version: 1.211.538.0

4. Failed Updates in Update History are:

Definition Update for Windows Defender - KB2267602 (Definition 1.211.176.0)

Definition Update for Windows Defender - KB2267602 (Definition 1.211.83.0)

HP - Other hardware - HP Wireless Button Driver

Definition Update for Windows Defender - KB2267602 (Definition 1.209.1186.0)

Definition Update for Windows Defender - KB2267602 (Definition 1.209.1172.0)

5. 12th November 2015.

6. Firefox current version is 42.0

7. no backup.

 

Windows Defender Update; Failure to install automatic update

*Original Title: Windows Defender Update

All my computers run Windows 10.

Since July 13, 2016 there is a failure of automatic update of the virus definition file.

My current version is 1.225.1289.0 and Windows Update and Windows Defender cannot download the latest version:

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Windows Defender - KB2267602 ( 1.225.2072.0)

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What went wrong?