The password is in the HDD. The original owner placed it there by chance (playing or meant to keep for himself). There is nothing you can do about it. I know cause I sold one like that on ebay and the buyer came across that password problem. When he sent it back, I got the password removed (I used several passwords for things) and the drive formated and installed OS fine after that. Good Luck.
For every problem there is a solution, for every solution there is a tech behind it.