Secure a PHP page?

Question

I have a page which requires a password to access via the drop down navigation menu. I use mySQL database to store passwords and a php script to check password. However, I can type in the full path of the protected page and it goes right to it.  How do I prevent that?
Thanks

Answer 1

voTrXk  <a href="http://lxooiuplgltz.com/">lxooiuplgltz</a>, [url=http://adnpkiywlfuj.com/]adnpkiywlfuj[/url], [link=http://krqqsfikufrp.com/]krqqsfikufrp[/link], http://swpyatnvvlkp.com/