Secure Web Development

I need some help on a client access page I have developed. Once someone goes to my website, http://www.myweb.com and they click on client access, they go to an ASP logon page which will authenticate a user and redirect them to the corresponding page. I want these pages to be secure. Here’s my problem. Let’s say that this is the URL for the end user’s page: http://www.myweb.com/clientaccess/company.html. Well, if you were to type this URL into the address box of the browser, you can accessthe page without any type of authentication and this info is highly sensitive. Can someone help me out with this? Is there something I can do in IIS? What can I do? Thanks, Jeremy