Hide / Disable GUI.Textfield in scene

hi! I'm back with another issue.

have a login screen in my scene that uses two GUI.Textfield boxes. one for username other for password input.

what im doing is when the user clicks the login 3d text (not gui button) a method checks to see if the info they entered is correct. if its not then game switches to another camera to show something diffrent in the scene that basicly says 'sorry wrong info try again'

problem is the GUI.Textfield boxes are still there.
ive done some searching and cant figure out how to make them hide until they go back to the regular login camera.

ill show you the code im using and maybe someone can tell me why its not working. note that once the user clicks the login 3d text and finds out the info isnt correct it takes them to the UserNotFound() function.

thanks!

here are two images that show whats going on:

Login Screen Try Again Screen

(P.S.) this is not the whole script. just the parts that i think matter in this case.

 private bool guiVisible = true;
 
 void OnGUI(){
         //GUIStyle myStyle = new GUIStyle ();
 
         //GUI.color = Color.yellow;
         GUI.backgroundColor = Color.white;    
         GUI.skin.textField.fontSize = 35;
         GUI.skin.font = (Font)Resources.Load("Fonts/MagicMedieval", typeof(Font));
 
 
         if (guiVisible == true)
         {
         GUI.contentColor = Color.green;
         userNameText = GUI.TextField(new Rect(520, 515, 545, 45), userNameText, 25);
         GUI.contentColor = Color.black;
         passwordText = GUI.TextField(new Rect(520, 635, 545, 45), passwordText, 25);
         }
 
     }
 
 public void UserNotFound()
     {
         guiVisible = false;
         UnityEngine.Debug.Log ("Did Not Find User");
         cameraSwitcher.SendMessage("ChangeCamera");
     }