Glad that out of the way.I don't usually deal with XP problems,but will as a sound problem.Locateing various options and setting might be slightly different from Wme.
1.Is this internal audio.if so get a pci card.
2.if not internal,what is it ?
3.What sounds are you complaing about ?
4.Have you done a directx sound test ?
5.Most important,speaker system type 2/1 etc.