Sony/Philips Digital Interconnect Format, or S/PDIF, is a type of audio connection that uses a special jack. On computer systems, the S/PDIF connection is typically used to output audio streams to digital sound systems, such as a home theater speaker system or a digital audio receiver and is found on sound cards and newer motherboards with on-board audio. Users who prefer to use an analog sound connection or another audio interface can disable S/PDIF output completely.
Click on the "Start" menu button, click on "Control Panel," click on "Hardware and Sound" and then click on "Sound." The "Sound" control panel will appear.
Select the "Playback" tab if it isn't already selected.
Right-click on the S/PDIF icon (it may appear as "Realtek Digital Output," "S/PDIF Output" or "S/PDIF," depending on your sound card or motherboard) and select "Disable" from the contextual menu.
Click "OK" to apply the changes and close the Sound control panel.
Re-enable S/PDIF by opening the Sound control panel and switching to the Playback tab. Right-click on the window and select “Show Disabled Devices” from the contextual menu, and then right-click on the digital output or S/PDIF icon and select “Enable.”
If there is no audio device connected to the port, the S/PDIF icon may not show up in the Playback tab in step three. Right-click in the window and click on “Show Disconnected Devices” from the contextual menu to display the S/PDIF icon.