BIOS Hard Drive Passwords May Be Specific to the Computer Type/BIOS Version

I recently moved a hard drive from a ThinkPad T60 laptop to a ThinkPad T400.  The hard drive had a BIOS password set, but it appeared to work normally in the T400.  I could boot, enter the hard drive password, and access the disk.  However, when I started having problems getting PGP to encrypt the hard drive, I decided to remove the hard drive password.  The T400 could not remove it – the option was grayed-out in the BIOS.  Luckily, I still had access to the T60, so I put the hard drive back in the T60 and was able to remove the hard drive password.  I have now moved the hard drive to the T400 and I am able to set/remove the hard drive password at any time.

Networking Encryption PGP BIOS