The tool to use is MHDD with the UNLOCK option:
http://hddguru.com/software/2005.10.02-MHDD/mhdd_manual.en.html#password
Hiren's 15.2 ships with
MHDD 4.6
EDIT: MHDD doesn't work with USB drives, you must connect it to a SATA port in your PC.
After unlocking the drive you need to disable the password protection with DISPWD or the drive will lock itselt again after you turn the PC off.
Either you need to know the user password (
usually the same as the laptop bios password) OR use a master password. In my case on the original Xbox hard drive the user password was widely known (TEAMASSEMBLY) but I don't know which works for your drive. Using a google search it seems that older IDE WD drives were unlocked with WDCWDCWDCWDCWDCWDCWDCWDCWDCWDCWD, I suppose it hasn't changed but you never know.
Another way to get the password is dumping the contents of the HDD's eprom or the hard drive sectors that store the password data but I don't know what program would do that. If you use the master password the hard drive will return to a RAW state for the obvious reasons.
All hard disks have a hardware password capability build in. This password is usually stored both in a chip on the HDD controller (the printed circuit board on the hard disk) and on the hard disk itself in a special hidden sector. Setting this password will make the hard disk completely unusable to anyone that doesn’t know it and not only on your computer, but on any computer. A lot of newer laptops will set the HD password together with the BIOS password, completely locking all the hardware. The data itself isn't encripted, it's just that the drive won't access any data until it receives the password. Swapping the controller of the protected hard disk with exactly the same controller from an unprotected HD will not remove the protection on most disks, as the password (together with most of the firmware) is also stored on the hard disk itself and both must check.
That being said, it isn't impossible to get the data back, just that it isn't possible for a person at a user level, you'd need to use specialist's tools for reading the platters directly.