It's the one I've just built, Sandra. I installed the sound drivers from the CD that came with the motherboard, but I'll have a look at the Asus site to see if there are any later ones. The board seems fairly up to date though, as the BIOS is dated 03/08/03, not that I know if that's relevant.
Joudi, it's not just one CD, and it's a brand new CD drive (DVD actually), so I wouldn't think it would need cleaning just yet.
I will check the connections again, and maybe move the connection lead to the other connector on the motherboard, to see if that has any effect. Other than that, I'm stumped.