Hi, You said
when the drive does not show in My Computer this means the drive is dead and no way to recover the info?
It does not mean that the drive is dead. It could be the interface in the External drive case that has gone bad and the drive is OK. Or it could be the power supply if the external drive has a separate power supply. Less likely a bad cable.
As for flash drives, most of the failures I have seen have been broken solder connections between the USB plug and the circuit board.
In that case a fine tip solder iron to resolder the broken connections after opening the case usually works. They never go back together right and I have only done it in the past to get peoples data back.
What Brand of external drive, Many can be opened and will have a regular drive inside. I have seen reports that Western Digital often are not standard inside. If they have a regular drive inside, then can be hooked up to a desktop computer and data recovered.
WD most likely does that so that You can not just buy the external drive, open it up and use the drive in a desktop computer.
In many cases I have seen a external drive selling for less than the same size internal. Not sure why.