Hide Upper Right "Register" Option

Hi, currently in my wiki, for administrative reasons, there is Admin as only user, everybody else is a Guest., but in the upper right corner still i have the register option and i cant find how to hide or remove this option from there, its possible ? WITHOUT change the skin, implement css vm templates and all this complicated issues (from my ignorant point of view, of course) Mmmm... there some good doc or tutorial about how to change the skin, for a css and Velocity ignorant ? Thanks !! Still trying to solve the Lucene plug-in problem.... -- A.U.S. Enrique Ferreyra Centro de Cómputos Red Megatone - Red Confina