How To Fix corrupted external hard drive

1) Check your Master/Slave/Standalone jumper settings and make sure they are correct and
don't conflict with another device on the same IDE channel.
2) Check for bent pins on the connectors.
3) Try a known good cable—Floppy and IDE cables often seem to go down the gurgler at the
worst possible time for some unknown reason.
4) Try a known good drive on your IDE channel and check the channel. If it doesn't respond:
• Try another IDE port (if there's two)
• Disable onboard IDE and try another I/O card (one that’s known to be good of course)
5) Try the disk in another PC.
6) Here's where it starts getting tricky. By now you must be reasonably convinced you have a
bad case of galloping disk rot. On some drives (not all), if you have an identical same model
drive, you can swap over the logic board. This will let you know if it is the embedded controller
on the logic board. With luck, your disk will roar into life and you can suck the data off onto
somewhere safe.
7) If your disk is making a hideous noise like a peg-legged man with a vacuum cleaner on a
wooden floor (whirrr, clunk, whirrr, clunk....), then it is likely you have a dropped head. This is
where you have start making decisions about how much your data is worth, because to go any
further is going to cost big time and may require factory technicians to try and repair the disk
in a clean-room environment. If your data was that important, then it would have been backed
up. (Of course it would have been, they all respond in loud voices)
8) She's dead, Jim. How fast can you type? In a nutshell, this is my summary of the death
cycle of a hard disk.