Sure, just go to
www.nvidia.com and go to download drivers, then click the appropriate options. (In your case, it would be Graphics drivers -> GeForce -> [operating system])
Download the file it gives you and install it.
BTW, I have KOTOR for PC and I have had no problems with sound. I do, however, get this little glitch that my characters sometimes turn away from the person they are talking to. It's nothing major, but it gets annoying sometimes.