Separate the two plastic parts that form the case of the usb pen, this may require levering using a knife, small flathead screwdriver, etc.
Resolder the usb plug to the circuitboard in its original position. If you have never soldered before, I would recommend asking someone more experienced, as the pins can sometimes be quite close together, and excessive heat can damage integrated circuits. Soldering tutorials can be found online.
ronnie, December 2007