Flash 5.0 – Help with the Intro Screen

Flash 4.0/ 5.0

I have a flash, which after some animation the menu screen appears (1 swf file)

What I’am look for is that
If the user / customer visits my site for the first time then the animation followed by the menu should be played, BUT
After visiting other section / pages & returned to the index page only the menu should appear.

I hope I’am clear 🙂

Thanks