var mainLoader:Loader = new Loader();
//create new URLRequest and fill it
var defaultSWF:URLRequest = new URLRequest("bear.swf");

//load the loader
mainLoader.load(defaultSWF);
//position the loader on the page
mainLoader.y = 0;
mainLoader.x = 0;
//add the loader to the page
addChild(mainLoader);

//*******************************************************

function step(event:MouseEvent):void {

removeChild(mainLoader);
SoundMixer.stopAll();

}

//event listeners which run function btnClick for CLICK event of each button

stepbystep_btn.addEventListener(MouseEvent.CLICK, step);