If you are looking for troubleshooting on the Intel Desktop Board DG31PR, we would like to inform you that the motherboard has been discontinued and the support we offer is through the website only, now as an additional recommendation please update your motherboard BIOS to the latest version, check the Operating System audio settings, check the header pin out on the Technical Product Specification and if the issue persists check for warranty on the motherboard:
Sorry if I'm posting wrong, but it was the only way I found to try to solve the problem.
Recently (about 2 days ago) tried updating the BIOS to see if I'd find any option to enable SPDIF, but still with the same option (for peripherals) to Enable / Disable the onboard audio or frontal audio
I realized that installing audio driver in Windows seven, the SPDIF option disappears
According to the motherboard manual configuration pins are right, and I could not identify if there is a jumper to connect
About a guarantee for a product of the year 2007 (according to the manual online), think no more warranty