A repair install may resolve your problems but you will need Win 10 install media which you can create after reading
https://www.google.co.uk/url?esrc=s&q=&rct=j&sa=U&url=https://support.microsoft.com/en-us/windows/create-an-iso-file-for-windows-10-38547366-1dcb-7afd-1726-9eb222d72705&ved=2ahUKEwibpuOd0fDzAhUEt6QKHcOZCTcQFXoECAIQAg&usg=AOvVaw255oipgN4Pru6dW1TBNlOLClick on the blue link in the page then scroll down the page for the instructions.
You will need an USB of at least 8GB.
Sorry for the long link for that but it didn't give me an option to copy the link for the actual ISO page.
When you have created the media, open Windows/File Explorer - insert the USB and double click on its drive.
This will open to its files where you would then double click on Setup Application.
This will start the repair install which won't affect your personal stuff or installed programs.
Hopefully this will revert the Permissions to default that you had changed.
However, you could first try booting up with the install media and select Repair your computer on the Install screen.
Navigate to the Command Prompt and enter these cmds -
bcdedit |find "osdevice"
For clarity that is a Pipe symbol before find and is the uppercase of \
Then using your partition letter instead of the X I have exampled, enter -
dism /image:X:\ /cleanup-image /restorehealth
sfc /scannow /offbootdir=X:\ /offwindir=X:\Windows
Enter exit to close the cmd window, remove the media and reboot to see if they have fixed anything.
You could perform another sfc /scannow in normal mode to see if it reports the same or no integrity violations.