Yamcha,
Just to confirm:
1. You've tried on multiple machines already?
2. You've tried a different USB cable right?
Then it could either the USB connection on the player or the board itself that's causing this issue.
If the USB device doesn't get detected in Windows XP and after trying multiple computers and USB cables, then it would seem that the problem is with the player itself.
I would suggest you contact UXcell (did you buy it from UXcell?) and I'm sure they'll be able to help you sort out the problem.
Email:
info@uxcell.com
Good luck.