Windows 10 User Account setup and defining

My current LT with Windows 10 Home during installs, etc now say "you don't have authority...".when changing, installing things that did not produce an error before.
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I suspect my "Account/User Profile" maybe corrupted but when I check my "Local Account" name, it says it is: "Administrator" .

To verify, I go to: "Change User Account Control", the STANDARD is checked, and if I check "ADMINISTRATOR" the "change account type" is greyed out.

Please advise.

It started when "CALCULATOR" just disappeared, then in a day or two, STICKY NOTES disappeared... so I went to: Microsoft STORE, press BUY and get the error "

This file does not have an app associated with it for performing this action. Please install app or, if one is already installed, create an association in the default Apps Setting range

All I get is this popup when pressing GET on any MICROSOFT APP.

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OH, changes, I found out my OS was OLD and spent last 3,4 days trying to get it updated. It now should be on: 1909 OS 18363.900 but problem did not go away.