Windows 10: My account says it no longer exists when I try to log in.

I use this account to play minecraft, and last night while I was asleep there were some unauthorized logins, and this morning I woke up to my account no longer existing. I know the email and password I used to log in, but even the Microsoft support says the account never existed and I don’t know how to fix this.

:)

 

Can't delete "emails and apps" account that no longer exists

I have an email account through a university I no longer attend that is included in my list of accounts. I receive constant notifications saying that I need to "update the password" for this account, but I can't because the account no longer exists. I also
can't delete the account from Windows because when I click "Manage" it sends me to a login page for the nonexistent email. Is there a way to get around this and remove the account from my computer?

 

Replace administrator account (that no longer exists) from laptop

Spoke to microsoft support and was referred to post something here to be seen by a technician as they were unable to resolve my issue. The reference number to the conversation is listed above in the subject (xxxxxxxxxxx). In summary my old account was
compromised and so I deleted it (hence it no longer exists) however I am still logged into it as an admistrator account on my laptop and would like to replace this account with a different one I have made.

 

Homegroup: Password from account that no longer appears to exist


My windows 10 was set up locally only - I did not use a Microsoft account.
Yesterday I set up Windows 2 step verification. I also logged in to some odds and ends as required during the day.
When I turned my desktop on today I was unexpectedly prompted for my windows live login instead of my local login. I couldn't, it appears, switch user to my local account.
It was a bit of a nightmare (my passwords are stored on my machine in Keepass, and are long random strings of characters that I certainly don't remember). I got there in the end after managing to reset my password on a different device (only just - I've only recently set up my email on a tablet - without that, I don't know how I would have got in to the desktop).
However, none of my mapped network drives connected. It turned out to be because the account was no longer linked to the Homegroup. When I try to login, my desktop, with Windows ID Login, is asking for the password as supplied by the same desktop, with the local account. However, from everything I can see, the local account no longer exists.

How can I reset the homegroup from the non existent account, so that I can set up a new homegroup?