Log off deleted Microsoft account?

I had been given a Microsoft account through my school with my school email address. I have now finished school and my email address and Microsoft account have actually been deleted.

However, the account & the Onedrive folder still exist on my laptop. I would like to remove them, but to do this I have to log in. However, when I try, I only get the error message: The user you specified does not exist.

I'm 100% certain that there are no typing errors in the user email.

Can I somehow deregister this account from my laptop?

Delete the folder and one drive