How to disable my Script and Gui

*Edit*I updated the script to

 function OnMouseDown () {
     GetComponent("StartGame").enabled = false;
 }

////////////////////////////////////////////////////////////

My Gui Menu is in my Script

 var mySkin : GUISkin[];
 private var cont : int = 0;
 
 function OnGUI(){ GUI.skin = mySkin[cont%mySkin.Length]; if (GUI.Button(Rect(200, 70, 200, 50), "Start Game")){ Application.LoadLevel(""); Debug.Log("Let the Game Begin"); }
 }

Now I want to be able to have an options in my menu as well. The problem is, If I click my Options Gui button, I want to disable all my other gui buttons. Here is the test code I have.

 function Start() {
 if(Input.GetMouseButtonUp(0))
   script = GetComponent("Start Game").enabled = false;
 }

What do I need to add to disable my other scripts that contain my gui menu. Right now it doesn't work. My start game script still works even after I press it.