usb is backward compatible so if a usb slot works, then it should handle the drive. it will of course run at much slower speed but it should work.
xp was not around when 3.0 came out for sure. i think2.0 was not very old either and not widely adopted at that time.
problem with xp is that it may need drivers for the drive itself to work. back in those days, the plug and play was not as good as it is now. most external drives back in those days came with drivers to install!! my guess is this is what the problem is rather than the usb drivers themselves.
i doubt there are drivers available for the drive itself so not sure if there is anything you can do.