Need help with a situation

Hi, I just need help to create a Login page for a client. My client is asking
me for a login page with this kind of security

- Each selected visitor will login one time only; if the visitors try to logon
again the page will not allow that.

How can I create and customize a page like this using Dreamweaver MX 2004

When you create your user account table, include a logged in column. Set it to
false initially and check the status during login. If false, let them in and
then set to true. If true, display an error message.