hide gui.label after an event

hi im using this script to serve as a timer and a game over script but when the timer hits zero, it still displays counting like 00: -1 00: -2 and so forth.

i have no idea how to hide the timer when it hits zero, any ideas? im a total newbie so please explain it a bit more thanks!

private var startTime;
private var restSeconds : int;
private var roundedRestSeconds : int;
private var displaySeconds : int;
private var displayMinutes : int;
var text : String;

//gui

var mySkin2 : GUISkin;
 var gameover: Texture2D;
 var permago: Texture2D;

var countDownSeconds : int;

function Awake() {
    startTime = Time.time;
    guiTexture.enabled=false;
}

function OnGUI () {
	GUI.skin = mySkin2;

    //make sure that your time is based on when this script was first called
    //instead of when your game started
    var guiTime = Time.time - startTime;

    restSeconds = countDownSeconds - (guiTime);

    //display messages or whatever here -->do stuff based on your timer
    if (restSeconds == 60) {
        print ("One Minute Left");
    }
    if (restSeconds == 0) {
       
        print (stagegameover.gochecker);
        gochecker = true;
        stagegameover.gostate = true;
        if(stagegameover.gochecker>2){
        	guiTexture.texture=permago;
			guiTexture.enabled=true;
		}
		else{
        guiTexture.texture=gameover;
		guiTexture.enabled=true;
		}
		//stagegameover.tryagain=false;
        //do stuff here
    }
   
    //display the timer
    roundedRestSeconds = Mathf.CeilToInt(restSeconds);
    displaySeconds = roundedRestSeconds % 60;
    displayMinutes = roundedRestSeconds / 60; 

    text = String.Format ("{0:00}:{1:00}", displayMinutes, displaySeconds); 
    
    GUI.Label (Rect (400, 25, 300, 400), text);
    
  
}

Put this code under “function OnGUI () {”

  if(restTime < 0){
        return; // All code below is ignored as it, erm... returns! :)
  }