Windows Store and Default apps not working

Thank you - that's what I recommended.

Now, before it's too late, create a new 3rd party disk image saved to external storage and continue to update that periodically.

Macrium Reflect is the most widely recommended (free is good, paid better).
Youtube videos, huge help file, forum write access only for paid customers, free product works but since Jan is no longer updated.

Hasleo (free) - Chinese- is said to have the best features of Macrium paid.

Aomei Backupper (free/paid) - Chinese- simple interface

Many threads, comments on these tools if you care to search.

Can I suggest you start your own thread with an appropriate title so it gets seen by members? Thanks!

Also give the history- when was last all well, what happened that may have led to this, whether you've had WU disabled or tweaked your system in any way, cleaned the registry.. and of course your full Windows build number (as prompted by the forum when creating a new thread). Please also state which apps you have problems with and provide relevant screenshots.

Are you using a 3rd party firewall?

I'd say create another user account and log into that to see if it has the same issues. If it doesn't then consider:

Account Profile Fixer

Before using that you should backup (copy to another drive) your appdata folders.

C:\Users\USERNAME\AppData

or

[Winkey+R]

then type:

%APPDATA%

Press Enter