Windows 10: cortana, start menu, and "modern" app won't work

Microsoft edge doesn't even have an icon on the taskbar, basically all "modern" apps just don't work and nothing happens when I click the start menu or cortana. I attempted a powershell solution but got nothing but errors. What can I do? regestry fix? microsoft fixit? every "modern" feature just doesn't work.

:)

 

windows 10

A critical error cames on the screen saying.. "Start menu and cortana aren't working" and the window (bottom left) won't work, HELP!

 

Last update caused all custom file associations to reset to defaults

It's clear to me that modern apps are still fully functional then, but they won't appear in the open with menu any more. So this removes the ability to use another default but occasionally quickly open a file with the Microsoft modern apps. For example I
use MPC HC for videos but would like occasionally to open video files with the Microsoft modern app via open with menu.