David,

First, if you have a 'name-brand' PC like Gateway, try going to their
website and getting the exact audio drivers for XP. (For example, Gateway can
find very specific drivers depending on what kind of serial number your PC
has. WORKED FOR ME! YAY!) It seems that my computer didn't like the 'generic'
drivers, and needed something a bit more specific.

Second, try updating your board drivers.

Hope that helps! :)