If you haven't set a password for the built-in Administrator, all recovery and reset options can be used without a password by Shift + Clicking the Restart button on the lock screen, even if all other administrators have passwords. Set a password for the "Administrator" account, and passwords (this one or another administrator) will be required before using recovery options.
Open Command Prompt as administrator and input net user Administrator *
Enter a new password. It could be the same as another administrator account, but preferably not the same as your standard account.