Removing “Other User” from startup screen
I assume you're using a recent version of MacOS X.

In System Preferences, you need the Users &amp; Groups panel.  Click the padlock to allow making changes.  You can then select the unwanted user account(s) and delete them from the list.

There's also a Guest User account.  To disable this, select it in the list of users, then untick "Allow guests to log in to this computer".