It's locked and you need to provide the correct password.
If you just bought it, ask the seller to give you that password, or reset/clear it for you. It he can't give you the password or can't remove it, ask for a refund, and only once you are refunded, return the laptop to him. It may be a stolen laptop...
If the seller is unwilling to help you or refund you, report the computer to the police as potentialy stoled good, and the seller as a potential thief or stolen goods reseller.
Electro, December 2012
