you can move the entire stage in flash so, what you want is possible but, it's not adivisable to move the entire stage.
it's better to put your frame x content in a movieclip and by controlling the movieclip's _y (or, y) property, move whatever you like to stage-top.
So if I track you right, when you click the nav, you want the nav to end up at the top of the view window...
this.y = this.y-navBar.y; //this' being what you want to move...'navBar' being what you want at the top
of course, that moves stuff in flash, not the page.
and that's an example of what i mentioned you almost certainly shouldn't do.