Why is none of my gui not working?

Every time i try and use a button it gives me an error saying ’ No appropriate version of ‘UnityEngine.GUI.Button’ for the argument list ‘()’ was found.’

If you look at the docs, http://docs.unity3d.com/Documentation/ScriptReference/GUI.Button.html, then you can see that gui.button requires 2 parameters. The first is a Rect defining position and size, and the second would be the contents of the button.