In the case of Gateway it's here as they have the same model with several different M'Boards it's a bit hard to say which driver you need but the Gateway site is listed here where you need to enter the Serial Number in so that you get taken directly to the correct drivers
http://tinyurl.com/2xgbl
If you can list the necessary drivers from a previous Windows Install like 2000 Pro it would be easier instead of the 3 different Sound Drivers that you have provided as it would then be possible to direct you to the correct drivers without involving any cost.
However if you are desperate for drivers they can be obtained from Drivers .Com for a small fee here
http://tinyurl.com/yxn2fb
Open this page and click on Solve your driver problems with Driver Agent and then when you are told what drivers you need download then directly from there.
Col