I believe your sound chip is a realtek ALC888S? Try googling for a driver for this chip, rather than relying on compaq, they don't keep their drivers up to date for systems past a certain age.
I don't know if realtek have/will release windows 8 drivers for this chip, but it's worth a go. The official windows 7 ones might work, but I think the whole registry works different in windows 8, so you may be out of luck.
Good luck anyway!