We're going to start the rejuvenation process by installing the hard drive in an external enclosure, which will make the job a bit easier. By placing the drive in an external enclosure, we can run all of our drive utilities from the Mac's startup drive. This will allow the utilities to work a bit faster, and avoid having to boot from a DVD or other startup device, which we would have to do if you were trying to revive your Mac's internal startup disk.
That being said, you can still use this process on your startup drive. Just keep in mind that we won't be including the steps to boot from another startup drive. More importantly, don't forget that this process will completely erase the drive that we're reviving.
The Type of Enclosure to Use
It doesn't really matter what type of enclosure you decide to use. Any enclosure that accepts your drive's interface should work fine. In all likelihood, the drive you're reviving uses a SATA interface; the specific type (SATA I, SATA II, etc.) doesn't matter, as long as the enclosure can accommodate the interface. You can connect the enclosure to your Mac using USB, FireWire, eSATA, or Thunderbolt. USB will provide the slowest connection; Thunderbolt the fastest. But aside from speed, the connection doesn't matter.
We used a handy external drive dock that lets us plug in a drive without any tools, and without having to open an enclosure. This type of drive dock is intended for temporary usage, which is exactly what we're doing here. You can, of course, use a standard enclosure. In fact, that may be a better choice if this drive is destined to spend the rest of its working life as an external drive connected to your Mac.
You can find out more about external drive enclosures in our guide:
We also have general instructions about building your own external drive.
There's one more reason why we like to perform this task with the drive connected to the Mac externally. Since the drive may have some issues, using an external connection insures that it can't damage any internal interface components. This is just another of our "don't take any chances" approaches that some may think is excessive.
On to the process of reviving the drive.