Sound card driver

If your computer came with a motherboard disc the sound drivers could be on it

click start control panel administration tools computer management device manager scroll to sound video and game controllers you might see a yellow question / exclamation? ! mark or a red X Right click to reinstall drivers

or you might download slimdrivers

http://download.cnet.com/slimdrivers-free/3000-18513_4-75279940.html

note: it will find all of your outdated drivers

this is a free driver solutions

which will automatically search for and find the correct driver
or
http://download.cnet.com/2000-20_4.html

just type in what you want or need be specific you might have to try a few times to get it right

also

http://www.innovative-sol.com/drivermax/

free program, paid update available

hope it helps