Hi Moore,
Welcome
Video card and Graphics card are two names for the same piece of hardware - this is needed to let you see things on the screen.
A sound card is a different piece of hardware needed to let you hear things through your speakers ( either the speakers built into your monitor, or separate speakers, depending on which you have connected ).
A driver is actually just a program ( i.e. a piece of software ) that connects your hardware to your operating system i.e. Vista.
You need separate drivers for your graphics card and your sound card.
Updating the drivers for your graphics card will not update the drivers for your sound card , and vice versa.
Hope that helps
SIW2
Click the middle icon at the top right of this post if it helps - thanks