Normal HDD passwords used in laptops are practically indestructible. I believe service agents have hardware solutions available, where proof of ownership is solid, but the cost may be high. The password is on the HDD, probably EEPROM in firmware but may also exist on system sectors so its effectively hardware locked. Also it may additionally be locked to a hash code from the BIOS to make it even harder if the drive is removed to another machine.
You cannot therefore LLF it as you simply cannot get any access to the drive without the password. You cannot format, update firmware, nothing. Even putting it in another PC will not work, the same issue will arise.
The password is there for a purpose and is a very robust mechanism, to protect the data. Either get a new HDD, get the password or pay $.
There is good info on Google but it takes a bit of searching.
I cannot easily believe someone would sell a PC in this manner, knowing it would be unuseable. Are you sure its kosher?