Click Start, type Sound into the Start Search field.
Select Sound from the results under the Programs list.Figure : Sound in results list
A Sound window opens. Do one of the following actions depending on what appears in the Sound window:
If there is not a Realtek HDMI Output icon shown as a playback device, go to the m9150f Software & Driver Downloads page, select your operating System (Windows Vista) and then click the IPIBL-LB Motherboard BIOS Update link. Use the instructions on the page to install the BIOS update. After the update has been installed, repeat these steps to enable Realtek HDMI Output.
If a Realtek HDMI Output icon is shown as a playback device, click the Realtek HDMI Output icon and then click the Set Default button. You should now hear sound from the speakers on the HDMI device that is attached to the computer.
HP Customer Support
HP Pavilion m9150f Desktop PC - No Sound from HDMI
Some HP Pavilion Elite m9150f computers are missing an HDMI audio configuration setting that enables audio through HDMI. For example, if a TV is connected to the m9150f using an HDMI cable, the TV will not play audio from the computer.
Before audio can be sent through the HDMI connector, the Realtek HDMI Output needs to be set as the default device from the Sound window in Vista. Set HDMI Output as follows:
Figure : Realtek HDMI Output option in the Sound window
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