Hard Drive Passwords
Some hard drives support passwords. These passwords can be implemented in computer's operating system, its BIOS, or even in the hard drive's firmware. Passwords implemented in the OS are the easiest to remove, those in the firmware are the hardest.
Sometimes people use the term "password" but the hard drive is really encrypted, and the password is used to unlock a decryption key. These passwords cannot be removed---the encryption key must be cracked or discovered through another means.
Disklabs (www.disklabs.com) is able to remove some forms of hard drive passwords.
Dell will assist law enforcement in removing the passwords from password-protected hard drives. You need to provide Dell with a copy of the search warrant and the computer's service tag #. Reportedly this can be done over the phone, once you have a good relationship with Dell.