Permission issue - this file does not have an app associated with it

My PC has one SSD drive with Win 10 Build 18362.476 and other files.

I started my PC as usual but this time I was offered the Win Installation Window. Restart didn't help and because I have very important files on this drive I immediately shut down my PC.

After that, I connected this drive over the USB external case to my Laptop (Win 8) to save files. I couldn't get access to the User folder, so I right-click it, go to security and I added a new group or username "Everyone" and gave it full control. Now I could copy files to my Laptop. Also, I removed some files from that drive (it had the only 800mb left of free space).

After that I returned back problematic drive to my PC and started it. This time Windows did load, but some icons lost their images, and when I try to run some programs or windows application I get a message:
"How to fix This file does not have an app associated with it for performing this action. Please install an app or, if one is already installed, create an association in the Default Apps Settings page"
The start was also not working, file explorer and some other features too.

I came to conclusion that permissions got messed up and because of that some programs could not access their files.

Now I tried to create a new owner and permission:


That gave me access to the Start menu but most other stuff is not working.

How can I reset my user permission to default? What can I do?