Computer has no sound, but the motherboard beeps.

[eyeCpc]

Well that was just in case a repeat attempt did manage to get something on. For the best guess here it seems Windows isn't even detecting the chip itself or you would be seeing a prompt for drivers come up at least once.

If the chip did quit on you then your option there is to go for a separate card. The quality heard on a good card usually passes onboard right by. Be sure to disable the onboard in the bios if you do end up buying one.