Hide Previous Scene when Press a link in Drop Down Menu

Hi.
I’m using Flash CS3. I’ve got my drop down menu navigation bar working. I’ve created buttons. I finally figured out how to link to other scenes on my flash moving using on release and frame labeling. (Most tutorials only tell you how to do get url to outside sites for some reason).

My issue is that when a button is pressed, the previous scene still shows.
For example, a person presses the home page button and the home page shows under the bar.

Then the person presses the contact page button. The contact page shows under the bar, but the home page is still showing too!

How do I get just the right page to show and get rid of the previous page(s) shown when the user wants to see a certain page?

Thanks.