HP EliteBook 840 G7 , modern security features mean there is no "paper" master code
If a "System Disabled" box appears with an 8-digit or 10-digit code, write it down. Visit a third-party unlock site like BIOS-PW.org hp elitebook 840 g7 bios password reset
What is a BIOS Password?
If the password is unknown and SpareKey was never configured, HP’s official policy for this generation of hardware is often a motherboard replacement. Because the security is hardware-bound to the BIOS chip, there is no software "backdoor" provided by the manufacturer for security reasons. Method 4: EEPROM Programming (Advanced/Technical) HP EliteBook 840 G7 , modern security features
If you see one of these on your screen, here is what HP is telling you: HP EliteBook 840 G7