I have a Toshiba Satellite with a radeon 4650 graphics card running windows vista 64 bit. I have an hdmi cable connected from the port on the laptop to the port in the back of my lcd tv. I have gotten it to work fine, until I did this...

When I had the display on the laptop and tv, I selected the option to only have the display on the tv. I clicked apply, and my computer screen went black. I looked up at the tv expecting to see my computer display, but it was also black. Now, every time I connect the HDMI cable, both screens are black. I've looked around to try to get back to this menu to put the display back on both my tv and laptop, but have been unsuccessful in finding it. The option to change the display appeared after I originally connected the HDMI cable.

How can I get a display back..?