If you are the registered original owner of the system, you'll need to call Dell (and pay for the call) to have the system unlocked.  You will be required to provide ownership documentation. If you purchased this system used, contact the seller.  If they cannot or will not provide the password, return the system to the seller for a refund.  
Help me to solve it. My out of warranty on November 4, 2018 Inspiron 15 3567 is displaying = This computer system is protected by a password authentication system. You cannot access the data on this computer without the correct password. Please type the system or administrator password.
Inspiron 15 3567, Password Authentication System