Realtek AC'97 Audio

Where do I get this sound driver? The one I downloaded had an unknown publisher.

Should that not be the correct one, IIRC this is an onboard soundcard, so the driver should be at your motherboard's producer's site.

Which one do I download for windows?

The problem is that the AC97 is on heaps (if not most) modern motherboards, and the drivers for one motherboard may not work properly on another. It took a while to find the win98 drivers for my old compaq ac97, because the usual drivers didn't work.

The AC97 is rather crappy anyway, if you want good sound get a proper plug-in card.