Determine what motherboard you have, and go out to the motherboard's website, and look it up by the model number which should be on the board. They should have driver support for you to download.
You may have to find them on several different websites
Driverguide, Driverscollection are two that should have at least some of them Softpedia has a few. Drivers collection has all of them but unfortunately they recently placed a 30 minute bandwith restriction on their downloads. ASRock support is rather useless and I will never buy another one of their boards simply because finding drivers is a pain in the behind. Good mobo's in general just driver support is horrible and whoever half assed the website should have been hung from a tree and beaten.