External Hard drive

I had a 200 gig external hard drive and used it as a backup for both of my
systems (Xp home W/sp2 and XP pro W/sp2) for about one year. Just recently
the hard drive does not show up in my computer or explorer I also checked
computer management under administrative tools and the drive did not show up
there either. I assumed the drive may have been damaged so I replaced the
drive in the external case with a new 160 gig drive already formatted ntfs.
Now when I plug the drive into the USB port is says that it found a new mass
storage device but it still does not show up anywhere. It also does the same
thing on both computers. I even uninstalled all of the USB devices even those
hidden under the device manager. After rebooting still the same. I am lost
any help would be great. Thanks Kirk