GUI suddenly missing in c# monodevelop?

I am new to unity, but I have used GUI before and I have spent the last half a day trying to figure out why when I type GUI., only a few things show up, like Destroy, DestroyImmediate, etc. The only way I can get things like Box is to use GUILayout.Box.

This is such a frustrating thing because it is SO SO basic. Blows my mind that I can’t figure out what is wrong.

Here is the code I am trying.

using UnityEngine;
using System.Collections;

public class GUI : MonoBehaviour 
	void OnGUI()
		//GUILayout.BeginArea (new Rect (50, 50, 400, Screen.width/2));
		//GUILayout.HorizontalSlider (50, 1, 100);
		//GUI.HorizontalSlider (new Rect(0,0,100,100), 1f, 0f, 100f);

Your Class is called GUI. When you type GUI in that class it looks in itself.

Either change the name of your class, or use the fully qualified name of Unity’s GUI class which is UnityEngine.GUI.