HDMI connection supports digital audio-video relay over a same cable for a TV and a Windows computer. Audio output over HDMI may not be supported by your laptop, as there is no stereo cable connected to your laptop. Take a stereo RCA cable with dimensions 1/8" to 1/8" stereo cable, on the basis of the input of your TV. Revisit the volume control settings of your laptop and TV for getting audio output. In Windows 7 Operating System choose the playback devices, pick an HDMI device not connected, and go to properties: now change the settings. Later, choose the driver tab, update the driver and the High definition audio driver gets detected. The high definition audio driver enables Operating Systems to provide audio output through your TV.
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?
I have been chasing this same problem for several days. None of the recommended solutions have worked to enable the HDMI cable between my Sony Media PC and the Philips TV. So, be sure the HDMI cable is connected and that the HDMI input on the TV is showing the correct type of input ("PC" on my Philips) and of course that your PC is on ;-)
In Windows 7 this is what worked:
Select the Playback devices (my HDMI device was listed as "not connected")
Select the HDMI device and right click "Properties"
On the next screen, for the device, click the Properties button
On the next screen, for the driver, click the "Change Settings" button
Select the Driver Tab, then go to the "Update Driver" button and select "Browse my computer"
You should see a "High Definition Audio Driver" listed; mine was listed but the driver installed was the standard IDT driver. Install the High Definition driver and then test the system; it should now be working. If you leave the screen open while you test it you can still "Roll back" the driver
Assuming your system is now working, close the various screens and sit back and enjoy your HDMI vision and *sound* :D
All my systems are Windows 7; I suspect you will find a similar option on a Vista machine.