So you need to install them, download the latest versions for your devices or laptop, whichever you have, from the manufacturer web site. Also, check to see that all your other drivers are installed. Windows will install many generic drivers, but some specific things it will not install.
Is this a desktop with a particular brand or motherboard brand or a laptop?
For recent hardware components W7 should always automatically get you a driver for your gfx card and motherboard audio (unless e.g. very old creative card and/or gfx card) - but you have to let windows 'search the' web for these drivers (or you can manually get it to do this under the hardware devices tab, where it talks about drivers).
Did you do this?
Also, as Realbeast said, you can (and should get into the habit) go straight to the manufacturer's site - especially to unlock full functionality (which W7 generics might not do).