That only installed the driver for the audio bus. you need to install the drivers for the audio chipset too. in your case drivers for adi audio chipset.
use a boot-able cd with norton ghost and follow the screens. it's very simple. it is important to ghost the system partition without booting into it because i found the ghosting of windows files that were in use by the system tricky to ghost. maybe it was my pc's guilt... what do you guys say?
Put a blank DVD in your DVD-RW drive then copy the file and paste it on the DVD drive. That's if you are using Win xp. If not, you must use a writing software. Google around to find such appz.
Better off, if the pc isn't sealed, have a look at the sound chipset and google around for its driver. also make sure that the audio codec is enabled (sometimes it only lets you chose "auto") in the bios. good luck and hope this helps.