If you are encountering audio detection issues when you connect your PC via HDMI to an HDTV or audio receiver, please update the HDMI audio codec to the latest version from the link below:

NVIDA HDMI Audio Codec 1.41

This driver will work under Microsoft's Windows XP, Windows Vista 32-bit and Windows Vista 64-bit.  If you are using Microsoft Windows XP, you may also need to install the Microsoft High Definition Bus Driver.  You may download this from the URL below:

Microsoft High Definition Bus Driver for Windows XP

If the Windows sound properties does not detect your HDMI audio device or shows as not connected, please download the Microsoft hotfix KB888111 which address this issue.  This hotfix applies to Windows Vista 32-bit only:

https://support.microsoft.com/kb/959458?sd=dell 

Should problems persist, check the HDMI cable.  NVIDIA recommends cable length no greater than 16ft.  Some older audio receivers may require firmware update for better HDMI compatibility.  If you are using an HDMI switch, it is possible that the PC is not negotiating a proper handshake with your display device.  Please connect your PC directly to your display device if possible.  If your display has multiple audio inputs for an HDMI source, you may need to force digital audio on your display to allow the PC to properly detect the audio capabilities of your display.