The AudioBox iTwo is not supported on XP thus there are no drivers for XP.
You can see that XP is not listed as a supported OS here:
http://www.presonus.com/products/AudioBox-iTwo/techspecs
You could potentially try using legacy drivers for other AudioBox units but this would be AT YOUR OWN RISK and would NOT BE SUPPORTED.
If you want to try, you can install the v1.2 drivers here:
http://www.presonus.com/support/downloads/audiobox-usb