Laptop sound on HDTV with HDMI cable (Windows 7)

I have my laptop hooked up to my HDTV with an HDMI Cable. The picture is great but the sound only comes through my laptop. How do I make it come through my TV?

Well there is the answer:

Control Panel ----->
Sound  ------>
Select Playback Tab ----->
Click On ATI HDMI Output Make sure your HDMI cable is connected to the TV.
Select Set As Default
Then Apply

Now everything (browsers, audio and videos should play on your TV. When you unplug the HDMI cable, sound should return to your laptop.

Any problem check your sound mixer to make sure everything is operational.