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);
     
   
 }