Hi
You are experiencing the same thing that I did after the Anniversary update.
My right click would stop working, my spell checker wouldn't work, Task Manager wouldn't open and my computer would get very loggy.
I couldn't open the command prompt either, and sometimes I couldn't shut my computer down.
On my computer it seemed to be related to Google Chrome somehow.
I uninstalled Chrome and my computer worked, I reinstalled it and it worked until I opened Chrome and then it would start the process all over again.
I tried putting in an older version of Chrome and that seemed to work, but then it updated itself and the problems started again.
Right now I'm using Opera, I used Revo Uninstaller to remove Chrome as completely as I could.
As long as I use Opera, or Edge it seems to be OK.
I ran all my malware programs, Sfc /scannow, every diagnostic I have and they all found nothing.
Weird, but I'd like to know if you find that Chrome it what's causing the problems, I thought that it was only me.
I imported all my favorites into Opera and Edge before I uninstalled Chrome.
Mike