Random MC from library

I need some help…

I have this banner and loads movieclips from the library randomly. BUT i don’t wan’t the same mc loads twice in a row. How do I avoid this?

// import tweening junk
import mx.transitions.easing.*;
import mx.transitions.Tween;
// some variables necessary for later..
var briefPause:Number;
// change this number for longer or shorter pauses between slides..
var pauseDuration:Number = 10000;
var index:Number = 0;
var curSlide:MovieClip;
stop();
//Slide Script Start 
// create an array of your slides
// if you add slides keep naming them "slide#"
//  and change the numOfSlides variable
function slideArray():Array {
	var myArray:Array = new Array();
	var numOfSlides:Number = 3;
	for (var i = 1; i <= numOfSlides; i++) {
		myArray.push("slide" + i);//ÄNDRA *1
	}
	return myArray;
}

// pulls the slides outta the library and fades them in..
// if there's already one on the stage, fade it out first.
function placeSlides(slides:Array):Void {
	if (briefPause) {
		clearInterval(briefPause);
	}
	var endNum:Number = slides.length;
	if (curSlide != undefined) {
		var tweenListener = new Object();
		var mySlideFadeOut:Tween = new Tween(curSlide, "_alpha", Regular.easeOut, 100, 100, 25);
		mySlideFadeOut.addListener(tweenListener);
		tweenListener.onMotionFinished = function() {
			fadeIn();
		};
	} else {
		fadeIn();
	}
	function fadeIn():Void {
		//RandomBegin-
		index = Math.floor(Math.random()*2);
		trace(index);//-Random End
		var mySlide:MovieClip = attachMovie(slides[index], "s", 23);
		curSlide = mySlide;
		var tweenListener = new Object();
		var mySlideFade:Tween = new Tween(mySlide, "_alpha", Regular.easeOut, 65, 100, 25);//45, 100, 25
		var tweenListener = new Object();
		mySlideFade.addListener(tweenListener);
		if (++index >= endNum) {
			index = 0;
		}
		tweenListener.onMotionFinished = function() {
			briefPause = setInterval(placeSlides, pauseDuration, slideArray());
			mySlide.pause_mc.onRollOver = function() {
				clearInterval(briefPause);
			};
			//Pause Slides onRollOver
			mySlide.pause_mc.onRollOut = mySlide.pause_mc.onDragOut = function () {
				briefPause = setInterval(placeSlides, pauseDuration, slideArray());
			};
			mySlide.pause_mc.onRollOver = function() {
				clearInterval(briefPause);
			};
			/*Pause next_mc Btn on all Slides
 			mySlide.content.slide01.next_mc.onRollOut = mySlide.content.slide01.next_mc.onDragOut = function () {
				briefPause = setInterval(placeSlides, pauseDuration, slideArray());
			};
			mySlide.content.slide01.next_mc.onRollOver = function() {
				clearInterval(briefPause);
			};
			mySlide.content.slide02.next_mc.onRollOut = mySlide.content.slide01.next_mc.onDragOut = function () {
				briefPause = setInterval(placeSlides, pauseDuration, slideArray());
			};
			mySlide.content.slide02.next_mc.onRollOver = function() {
				clearInterval(briefPause);
			};
			mySlide.content.slide03.next_mc.onRollOut = mySlide.content.slide03.next_mc.onDragOut = function () {
				briefPause = setInterval(placeSlides, pauseDuration, slideArray());
			};
			mySlide.content.slide03.next_mc.onRollOver = function() {
				clearInterval(briefPause);
			};
			
			/*mySlide.onRelease = function() {
				trace("PUT LINKAGE SCRIPT HERE");
			};*/
		};
	}
}
//  sets everything in motion..
placeSlides(slideArray());