How to work with removeChild() .. HELP

Firstly,

how do I set the buttons to only be selected ONCE , if another button is clicked … it will give no response.

Secondly,

what do i do to clear the image from the UrlRequest from the selected buttons (image will be displayed) with removeChild

As you can see below, all the buttons can be selected … all at once. which is wrong.
and also, the removeChild will only work without error #2025 if two buttons (and two images) were shown. which is also wrong.


stop();


aa1.addEventListener(MouseEvent.CLICK, ona1Click);
bb1.addEventListener(MouseEvent.CLICK, onb1Click);
cc1.addEventListener(MouseEvent.CLICK, onc1Click);
next1.addEventListener(MouseEvent.CLICK, onNext1Click);
home1.addEventListener(MouseEvent.CLICK, onHome1Click);




var Q1a:Loader = new Loader();
var Q1b:Loader = new Loader();
var Q1c:Loader = new Loader();
var Q1next:Loader = new Loader();
var Q1home:Loader = new Loader();


//the name of the function has to match what you're calling from the event listener
function ona1Click(evt:MouseEvent):void {


var myQ1a:URLRequest=new URLRequest("wrong.png");
Q1a.load(myQ1a); 
addChild(Q1a);


Q1a.x=320; 
Q1a.y=180;
}


function onb1Click(evt:MouseEvent):void {


var myQ1b:URLRequest=new URLRequest("tick.png");
Q1b.load(myQ1b); 
addChild(Q1b); 


Q1b.x=320; 
Q1b.y=260;
}


function onc1Click(evt:MouseEvent):void {


var myQ1c:URLRequest=new URLRequest("wrong.png");
Q1c.load(myQ1c); 
addChild(Q1c); 


Q1c.x=320; 
Q1c.y=340;


}


function onNext1Click(evt:MouseEvent):void {


removeChild(Q1b);
removeChild(Q1a);


gotoAndPlay(2);


}


function onHome1Click(evt:MouseEvent):void {
gotoAndPlay(17);
}

HELP me.