GUI box overlapping when reloading the scene

Uh, this is a really annoying problem. the following script draws a GUI box (the score)on the screen and when the player reaches a certain score, the player is given the option to play the level again. When I click the button to reload the level the GUI box should only be drawn once every time I reload the scene, but when I click the replay button it reloads the scene and draws another box, overlapping the previous one. Does anybody know how to fix the problem? thanks

#pragma strict

var items = 0.0;
private var showGUI : boolean = true;

function OnGUI () {
	
	if(showGUI == true)
	{
			GUI.Box(Rect(10, 10, 100, 20), "items: " + items);
			if(items >= 6)
			{
				win();
			}
			
	}	
	
	else
	{
		showGUI = false;
	}
}

function win()
{
	
	GUI.Box(Rect(Screen.width / 2, 5, 100, 20), "You Win!");
	
	if(GUI.Button(Rect(10, 30, 100, 20), "Play Again"))
	{
		Application.LoadLevel(2);
	}
	
	//GUI.Button(Rect(10, 50, 100, 20), "Next Level");
}

Sounds like DontDestroyOnLoad was called somewhere on the game object that’s holding your box script.