You are the only human user, there should be several other users on the PC that windows uses to carry out operations for you. These include System & TrustedInstaller, among a few. Its not a good idea to remove their access as windows won't work well.
Local user accounts are only created on that PC, they aren't always admin accounts unless made one after creation.
Microsoft Accounts exist both on PC and can be used online on the Microsoft website. If the user name and password works here, its an MSA -
https://account.microsoft.com/account?lang=en-us&refd=www.google.com
if its an MSA, its possible your current user profile is corrupt,
there is a simple solution, make a local user account and use it.
make a new local account and make it admin -
https://support.microsoft.com/en-us...ndows-10-20de74e0-ac7f-3502-a866-32915af2a34d
while logged into user that has problems, go to C:?users folder
copy the contents of the old users folder onto the new user, giving it full access to all files on PC now.
logon to new user, do you still have problems?
if it fixes problem, its easy enough to switch to new user and you can even link it to the same email address as 1st user if you wish. You shouldn't need to reinstall anything.