I have a new Toshiba Satellite L775 with HDMI output.
I wanted to connect the notebook to my TV for looking pictures via HDMI.
But it didn't work.
I connected the notebook with HDMI wire to my Samsung-LCD-TV.
Both, wire and TV already work. (Normally I use the wire for receiver to TV, without any problems).
I tried to change the output with Fn+F5 to TV-monitor (or TV-monitor & notebook).
But the TV doesn't detect the notebook, anyway.
I agree with Feliks… if the LCD TV supports different HDMI ports, you should ensure that the TV has been set to the right HDMI port.
Choose in the TV settings the right HDMI port and then you could use Fn + F5 in order to switch to the TV output.