recovering from a "broken" HD

The Seagate Barracuda 500gig HD (for data use only. OS is on a SSD) on my PC has gone wonky. The PC would not boot properly, kept freezing, and finally the drive vanished from the BOIS. Leaving it connected to the MB caused the boot time to rise 20x or more. Removing it, the PC boots properly.

I have the contents backed up until yesterday, so there is minimal missing (probably only 0.1%) but have you any ideas on how I might be able to recover the rest?

I have a 2TB WD Green arriving tomorrow, so I will have a fully functioning PC then.

A bit more information for you.

With the dodgy drive attached I can not boot the PC from PUPPY either. So I am guessing its the control software in the drive causing the problem, and as such its probably terminal.

Ontrack, DriveSavers and Datarecovery are three well-known and respected* companies that can attempt to retrieve files off of a 'dead' hard drive. Pricing typically runs between a few hundred to a couple of thousand dollars (US).

There is no guarantee that usable data will be recovered however. If a drive is too damaged, the data is effectively gone. Also, if a drive was encrypted and the customer doesn't have the encryption key, recovery becomes extremely unlikely. Many hard drive manufacturers sell self-encrypting drives, with the decryption key on the drive's circuit board. In those cases, data-recovery requires the original, working circuit board.

Physical damage can leave a drive permanently unreadable. If the read/write heads have scraped the magnetic coating off the platter, there's nothing to recover. Dropping a drive with glass platters can shatter the platters, and no one is going to get magnetic bits off glass shards.

Overwriting files -- intentionally or otherwise -- renders the erased bits unreadable. Overwriting a sector once is just as secure as the fabled Gutmann method, which rewrites sectors 35 times. Today's drives pack data so tightly there's no room for ghosts of previous bits.

*Western Digital "Platinum Data Recovery Partners"