On Logins and MDI Close Buttons

Let's say you have a useraccount table which stores data about the user accounts. What if the system is run fron scratch (with the database having no input whatsoever, meaning, there are no existing user accounts as well)? How are you going to have the user login to the system?

Would you incorporate a backup admin into the login form (eg: a backup admin user with admin and pass as its username and password, respectively)? I did this, but limited the account's authorization to making an admin-level account. Suggestions?

How do you make sure that the database connection has already been closed? Is there any method we can use to do that? What event should I use when making sure that the database connection has already been closed (particularly when a form is about to be closed)?

And how can I disable the close button on the MDI Form (and disabling ALT+F4)?

Anyone?