Just bought a 2007 Acura tl of a private owner , when I was purchasing the car before I drove off with it the owner tried to input the code for the navigation and radio aparently he blocked it or something because after the 3rd time the screen turned black. Now it wont work does anyone know what I can do to fix this problem. I also took it to the dealer after but they said the navigation / radio has no power and needed to purchase a new one but I mean how does it not have power if I see a black screen everytime I turn on the car. Any suggestions ?