OnEnterFrame Help

hey guys, first time posting here and a novice at actionscript. Basically im trying to build something like a carousel, but with using the keyboard arrow keys. If a user hits the left arrow key the onEnterFrame event should move to the next menu item and stop. The logic I used for this is if the x position of a movieclip is at 0, then set the speed to 0. Unfortunately what happens is that while most of the movieclips (menu items) stop, some trail a little off and end up having a lead on the others, leading to overlappings and such. The code is as follows:
(note: all the movieclips (buttons) have linkage identifiers, and are attached to the stage)

var centerX:Number = Stage.width / 2;
var speed:Number = 0
var beginX= 0;

var begin:Boolean = true;

for(var i=1;i<13;i++)

{
var t = this.attachMovie(“button”+i,“b”+i,i+1);
t._x = beginX += 35 ;
t._y = 35;
t.onEnterFrame = mover;
}

function mover()
{
if (this._x == centerX && begin == false )
{
this._xscale = 150;
this._yscale = 150;
speed = 0;
}
else
{
this._xscale = 100;
this._yscale = 100;
}

this._x += speed;
if (this._x &gt; 420)
	this._x = 0;
else if (this._x &lt; 0)
	this._x = 420;

}
var keyListener:Object = new Object();
keyListener.onKeyDown = function() {
switch (Key.getCode()) {
case 39:
begin = true;
speed = 5;
break;
case 37:
begin = true;
speed = -5;
break;
}}
keyListener.onKeyUp = function() {
switch (Key.getCode()) {
case 39:
begin = false;
break;
case 37:
begin = false;
break;
}}
Key.addListener(keyListener);

Come on guys…no suggestions at all??