Are you sure that the problem is with the NFORCE driver, or could it just be that your volume level is muted, or that the soundcard wasn't recognized?
Basically, if you've downloaded and installed the current NFORCE drivers, then the installation process will ask if you want to install the network driver and/or the audio driver. Assuming you answered Yes to both, and there were no errors thrown during the installation process, then presumably the drivers are OK.
Here's what I'd do: as root, run
which will look for and configure your sound card. (Make sure your speakers are plugged in correctly, the volume is up, etc). Next run
which will all you to adjust the various volume settings. (Use the right/left arrow keys to travel through the different settings and the up/down arrows to change the volume) Oftentimes the volumes are muted by default, so things may actually be working just fine, it's just that the volume is zero.
Good luck with it, please post back with your results