Stopping FLVPlayback when leaving a frame

1

hello, can anyone help please?
I’m totally new to as3. I have made a simple 4 frame web page that runs OK. I have a video playing at frame 2 (“medical”). Whenever the browser changes to another frame (page) the video continues playing the sound track in the background. When returning to the “medical” frame, it does not show any image but the sound continues in the background. When clicking on the stop button nothing happens, when clicking on the play button the video starts playing again on top of the previous video audio, hence one can here a mix of the two audio tracks.:m:
I imported the video directly into stage, hence the FLVPlayback was added. I see no code for this part that I can override. The only code I wrote for the navigation buttons is as follow:

//CODE TO CREATE 5 BUTTONS

import flash.events.MouseEvent;

stop();

//this script creates the functions for the pages

function gohome(e:MouseEvent) :void{
gotoAndStop(“home”);
}

function gomedical(e:MouseEvent) :void{
gotoAndStop(“medical”);
}

function gosponsors(e:MouseEvent) :void{
gotoAndStop(“sponsors”);
}

function gocontact(e:MouseEvent) :void{
gotoAndStop(“contact”);
}

function gosponsors2(e:MouseEvent) :void{
gotoAndStop(“sponsors2”);
}

//this script attaches the functions (above) to the corresponding buttons

header1_mc.homePage_btn.addEventListener(MouseEvent.CLICK, gohome);
header1_mc.logoPage_btn.addEventListener(MouseEvent.CLICK, gohome);
header1_mc.medicalPage_btn.addEventListener(MouseEvent.CLICK, gomedical);
demo_btn.addEventListener(MouseEvent.CLICK, gomedical);
header1_mc.sponsorsPage_btn.addEventListener(MouseEvent.CLICK, gosponsors);
header1_mc.contactPage_btn.addEventListener(MouseEvent.CLICK, gocontact);
header1_mc.sponsors2_btn.addEventListener(MouseEvent.CLICK, gosponsors2);