I have Ubuntu 8. Sound doesn't work. I have Realtek HD. This what i have done before but not working.

sudo vi /etc/rc.local
add “modprobe snd-sb16″ (before exit 0)
write and quit

You may need to update your BIOS

I had sigmatel HD audio on an intel chipset in a dell PC, and to get sound to work in linux (and vista too, oddly) i needed to update the BIOS.

Check the board manufacturers site. Exercise caution with regards to flashing the BIOS. Best to read up on it beforehand, and only apply it if the release notes state that it will fix sound detection.

Oooo, i did it once and killed my previous board. Lets not listen to the music then.

Its generally faiely safe. Just make sure you dont shut off the PC during the process.

Bad news is you will generally need to be running windows to do the flash

If i am brave enough i will do. Ithink there is a live bios update in Asus's site for me.

As I said, ensure that thats what you actually need. It was the solution for me but maybe not for you.

perhaps ask on the ubuntu forums?

i have just updated my bios via live asus update. I formatted my PC. When i install all the drivers for mainboard, i have seen a folder called "Linux". Guess what was in there. Driver of Realtek for Linux.
I will try it later.

Sweet. Give it a go, but it should be built into the newest kernel already.