Windows 10: Unable to enable Windows Defender and update Windows 8.1

I am using windows 8.1 enterprise. I installed AVG Security, AVG Tune-up Utilities. Last week when I started my laptop it atomically started installing window 8.1 build 9600. Thereafter, my laptop was not working properly. Therefore, I restore my system in previous condition. Run Windows Defender scan which found some viruses which were removed. However, thereafter my windows defender is not working. After trying everything I am unable to enable Windows Defender. Any Expert please guide me how can I enable Windows Defender. I am also unable to update My windows 8.1.

:)

 

SEtting up automatic updates for windows defender on windows 8

I have found this on the internet en have set up a task for automatic definitions update for Windows Defender but a window pops up when this starts to run.
Is there a way to set this without any window popping up so that it just runs in the background?

Now I'm using
"C:\Program Files\Windows Defender\MpCmdRun.exe" -SignatureUpdate -MMPC

I'm currrently using it as described here:
https://forum.raymond.cc/threads/let-your-windows-8-defender-update-itself-automatically.34359/

 

Windows 8 failure configuring updates and reverting

I agree 8 is awful! It's not for me though... I replaced a broken screen in a Win 8 laptop that was given to me and I am going to give it for free to someone that can't afford one so they can do homework at home. Yes I took it from 8 to 8.1 back on 10/09/2014. This is what I posted there...

"Great post! I found a similar one. I would like to point out that you may want to edit your OP...

1. Step 1 should read to disable AUTOMATIC updates, not disable manual updates.

2. KB2871398 should really read KB2871389

I would like to say that KB2917499 may also be needed as it was in my case. I also had to run the Windows Update Troubleshooter after installing those 2 updates. After these steps I was able to begin my 8.1 download from the Microsoft store. I don't know if it made a difference or not, but I also went into the Bios and disabled "Secure Boot."

It was a helpful post. Thanks!

 

Unlocked Realtek HD Audio Drivers Windows 7 & 8 (With Dolby Digital Live and DTS Interactive)

DTS supported natively by Windows 8/8.1 and it should work on windows 10 too just DDL require to unlock your driver .