Did you run the "Save Remove" function before unplugging it?
If you don't use the "Save Remove" function before unplugging a USB Storage device the drive can be corrupted. The easiest way of correcting the problem is to work out which PC you last used the device successfully with. Plug it back in and run the "Save Remove" function before unplugging it.
(To run Save Remove left-click on the "Safely Remove Hardware" icon in your System Tray and select the device from the popup menu.)
Dan
September 2005