|"i was just wondering how do you know they are the drivers"|
I went to the ASUS site & looked up the specs for the A8N-E. The board is based on the nVidia nForce4 Ultra chipset & uses the Realtek ALC850 sound chip. Rather than hooking you up with the drivers at the ASUS site (which are outdated), I went directly to nVidia & Realtek & found the most recent drivers available.
And you'll need Service Pack 3 for the HD Audio...if you don't have it, you can get it here: Windows XP Service Pack 3 Network Installation Package
Make sure to save a copy in case you ever have to reinstall it.