Hi!
At this point, the drive is probably toast. For the next time, invest in a
backup device, such as another hard drive in an external cabinet. They do
cost money, but the price is cheap if you're making regular backups to it
and find that you suddenly need one. Words don't describe how glad you'll be
if this ever happens. Trust me.
Power the drive up and see if it seems to come online normally. You should
hear a smooth spinup, some soft clicks as the drive initializes and then
nothing but spinning. If you hear loud repetitive clicking, nothing at all
or the drive just spins down, you can bet that something internal to it has
failed. Putting it in the freezer as another poster suggested might work. If
it does, hurry to get your data off of it. You might wish to put it in the
USB enclosure and freeze that entire unit with the power and USB cables
connected. That way you could keep the drive cold while getting data off of
it. Let it get down to temperature before you power it up.
If the drive does seem to start up normally, you're probably looking at a
failure elsewhere on the disk or a file system problem. A manufacturer
supplied disk diagnostic or data recovery utility (such as GRC's SpinRite,
which does work quite well if a drive isn't too far gone*) can help a disk
that is still able to run. Beware of utilities that simply "give up" on
unreadable data and toss it away. This can leave holes in your files.
For file system damage (which is unlikely, as the drive should still be
visible in system setup and as a boot device), a "disk editor" or the file
system repair utilities that come with your OS might help. A disk editor
software program can give you a look at the raw contents of a disk that is
functional but whose file system is so trashed that it isn't recognized by
the operating system or its file system repair/check tools.
Finally, if you are really desperate, you can try to buy a known working
drive from eBay or other secondhand equipment sellers. If you do that, try
to find a drive that matches yours as closely as possible. Form factor and
firmware level are important. When you find one, you might be able to swap
the controller boards from one drive to another. This may not work, and if
it does, there will be enough differences between drives (defect tables,
startup parameters, etc) that read errors and difficulty will be inevitable.
Or you can contact a professional data recovery service, which probably has
the greatest odds of success out of any procedure mentioned here. These cost
lots of $$$$, however.
(*I say this as nothing more than a very pleased customer of the Gibson
Research Corporation. I have no affiliation with that company or any of its
employees. I have seen more than a few drives that were simply too far gone
to save, but for many, it was able to perform significant if not total
recovery of the data on an ailing drive. It even works on floppy diskettes
if you're still using any. It also works great to help "certify" new and
unproven drives.
http://www.grc.com/)
William