Says its just to log in but doesnt work

so im trying this on my school pc to remove the admin password or log onto an admin account and use that instead, and thing is, everything works fine when booting and everything, but once i choose "remove password" or "change password" it either doesnt find the user even tho im taking it straight from the "!users" or it says "done, now just boot" and then i try logging onto the account and it says the name or password is wrong, u think u know whats wrong?

can you try to use !shell and then type net users and check the users ? btw if its online account then you cant unlock it