I have no audio from my LCD TV (samsung lns4041d) while connected via HDMI cable through a Toshiba Satellite X205-S9800. I've tried messing with the controls on both the notebook and tv yet nothing happens.
I had the same issue connecting my Win 7 Laptop to my 40" Samsung LCD. Tried this simple trick and it worked!!
Right click on audio icon (in the system tray/bottom right of desktop) and select Playback devices, on window of Playback tab, right click on Speaker and select Set as Default Device, apply OK, then play you music/video.
You can configure and test sounds..
There could be a slight delay. Wait for a couple of minutes.