Unload event for external swf[urgently need help]

Question

hi all master,
iI've mp3, eksternally loaded and I controlled from main time...
the bugs are
1. If I wanna go to another .swf file, i still can hear the sound...
2. if I click the button wich linked to mp3.swf, the sound/song are duplicated by2, and then if I click again the sound are duplicated by3...
how I can fix this problem??? oia, the buttons to call another swf are only in main swf,
and here is the code:
//zhe button
var Xpos:Number = 140;
var Ypos:Number =100;
var swf:MovieClip;
var loader:Loader = new Loader();
addChild(loader);
// Btn function
function btnClick(event:MouseEvent):void {
    if(loader)
        loader.unload();
        loader.unloadAndStop();
        removeChild(loader);
        loader=null;
    loader=new Loader();
     var newSWFRequest:URLRequest = new URLRequest("swfs/" + event.target.name + ".swf");
     loader.load(newSWFRequest);
     loader.x = Xpos;
    loader.y = Ypos;
     addChild(loader);
// Btn listeners
shout.addEventListener(MouseEvent.CLICK, btnClick);
song.addEventListener(MouseEvent.CLICK, btnClick);
gallery.addEventListener(MouseEvent.CLICK, btnClick);
about.addEventListener(MouseEvent.CLICK, btnClick);
So, anybody can help me???

Answer 1

then you can use:
//zhe button
var Xpos:Number = 140;
var Ypos:Number =100;
var swf:MovieClip;
var loader:Loader;
addChild(loader);
// Btn function   
function btnClick(event:MouseEvent):void {     if(loader!=null)
       loader.unloadAndStop();
        removeChild(loader);
        loader=null;
loader=new Loader();
     var newSWFRequest:URLRequest = new URLRequest("swfs/" + event.target.name + ".swf");
     loader.load(newSWFRequest);
     loader.x = Xpos;
    loader.y = Ypos;
     addChild(loader);
// Btn listeners
shout.addEventListener(MouseEvent.CLICK, btnClick);
song.addEventListener(MouseEvent.CLICK, btnClick);
gallery.addEventListener(MouseEvent.CLICK, btnClick);
about.addEventListener(MouseEvent.CLICK, btnClick);