Hi there,
I lent my friend my USB drive (average DSE fare - 2GB) to copy a couple of files. He pulled my USB drive out without unmounting it, and now no USB drive on his computer works. He uses an external HDD for everything, and this has basically hamstringed his use of his computer. He tried everything he found, including uninstalling and then reinstalling drivers, and it's not a conflict of drive names. We reinstalled a remix of XP Pro this evening, and it too has failed to detect USB drives (which suggests a hardware problem).
Any time a USB device is plugged it, it is detected, then not another squeak about it from the computer. The Device Manager when it's plugged in lists both my USD drive and his external as "USB device not recognized". I tried to mount my USB drive in Mac Puppy Linux (Puppy Linux), and MiniMe2008 (PCLinuxOS) and wasn't successful, though this could've been my own ineptness.