Get a print screen of your device manager. In XP:
1. open Windows Explorer
2. right click on My Computer and choose Properties
3. click on the Hardware tab
4. click on the Device Manager button
5. click on the plus next to the hardware you want to see
I usually expand the ones for display adapter, network adapter, modem (if you still use one), sound/video controller and any other hardware that you bought for your PC that plugs into your PCI slots. Print screen that and attach it here so we can see if XP have your drivers.
EDIT: Forgot to ask. Was XP the original OS or XP was installed ontop of another OS? Did you build this PC or did you buy it from a store like CompUSA, Dell, etc?