THAT is wierd. Did you have a massive power surge or something that could have blown the power on the external and somehow fry the internal? I have never heard of this happening. Your external drive has its own power supply, correct? Do you have any LEDs on it that light up or anything? It almost sounds like the external drive is not getting any juice, and thus, not spinning up, which would cause Windows to see nothing...
I would say you need to open the shell of the external, find out if it is IDE or SATA, and then get another enclosure that supports the capacity of the drive, hook it up and see what happens. What make/model/size is the external?
Bart