Depending on your level of technical comfort, these are the primary ways to address a locked BIOS:
stores its BIOS administrator password in non-volatile EEPROM/flash memory. It requires zero electrical power to preserve data. How To Reset Bios Password Hp Elitebook 840 G3
Forgetting a BIOS password on a business-class laptop like the HP EliteBook 840 G3 Depending on your level of technical comfort, these