Helping people with computers... one answer at a time.
Your options for what to do with a dead hard drive depend on the cause of death, and the possibility of resuscitation.
Anticipating the inevitable, how can I reuse or erase a "dead" hard drive?
It depends on just what the definition of "dead" is.
In some cases you can resurrect the "dead" drive, either long enough to recover the data on it, or perhaps to simply begin using it as a functioning drive once again.
In other cases it's best to just put a stake through its heart. And I mean that almost literally.
Drives can stop functioning for a variety of reasons, some of which are more fatal that others. For example a bad sector in the wrong place could make the drive appear to be completely unusable, but might be corrected with software. On the other hand a failure in the drives internal controller could render any attempts to reuse the drive completely hopeless.
Hence ... it depends.
So, when faced with a "dead" drive, here are the steps that I take:
Unplug the machine containing the drive for 5 minutes.
I know, I know, this seems either pointless or obvious to most. What could this have to do with the drive? And wouldn't someone have done this before calling the drive "dead"?
The fact is on many machines even when the machine is "turned off", there's still power applied to many components within the machine - quite possibly the drive or drive controller. If the drive has gotten itself into a "confused state" (a highly technical term, I know), sometimes only a true and complete removal of power will reset it completely.
It doesn't always work, but it's cheap, easy, and saves a whole lot of time and trouble when it does.
Run CHKDSK /R.
This assumes, of course, that the drive is not so dead as to be invisible to Windows. If the drive can be seen by Windows Explorer, then open a Windows command prompt and type CHKDSK /R D:, replacing "D:" with the actual drive letter. "/R" instructs CHKDSK to search for and attempt to repair bad sectors.
SpinRite is not a free program, but particularly when faced with possible data loss it's worth its weight in gold.
Spinrite performs what can best be termed a lossless format of the drive. By that I mean that it exercises and rewrites every sector on the hard drive without losing the data on the drive. In fact, it does just the opposite: quite often it will recover the data that may have appeared to have been lost. It identifies sectors which are permanently bad and causes the drive controller to take those sectors out of service, and in doing so return the drive to full functionality. Dead and unbootable drives have frequently been restored to health with Spinrite. And even if they're not completely healed, they're often "healed enough" for data recovery before the drive is discarded.
Move the drive to another machine.
Sometimes Spinrite will not recognize a drive that Windows does. Often this is because the BIOS on the machine doesn't actually recognize the drive or the drive's full capabilities. In cases like this I'll actually physically move the drive to another newer machine for Spinrite to work its magic. In addition, this can also sometimes expose problems with the original machine's connection, controller, or configuration if the drive magically starts working when plugged into another machine.
If none of the above work, then this is about where I give up. It's possible to keep going, though. If the data on the drive is valuable you may consider a data recovery service, but this can get very expensive very quickly.
You actually didn't mention data recovery, only drive reuse. It's at this point where the drive is in all likelihood not fit for reuse and should be discarded.
Discard the Drive
Normally with a working drive I recommend running a secure delete utility on the drive to completely erase everything that's on it prior to discarding it. But we don't have a working drive. The problem, though, is that someone could perform advanced data recovery on it after we've discarded it. By that I mean they could, for example, send it to a data recovery service. They'd have to be motivated to do so of course, but the point is that the data is most likely still on the drive, even if the drive's not working.
This is where I put a stake through its heart.
As I said I mean that almost literally: I physically destroy the drive by drilling several holes through it. Or I open the case that you're never supposed to open and pull the plates apart. Or something. The point here is that I do what I can to prevent the drive from ever being read again by anyone.
Note: so called "bulk erasers" or just big magnets don't work. They're actually not strong enough to penetrate the drive's enclosure and affect the drive's magnetic media. (And even if you did, with a broken drive how would you know to be sure?)