Press the Fn + Esc keys to toggle Function Lock on or off
Check for an Fn Lock key on the keyboard and press it if available
Enter BIOS/UEFI setup by restarting and pressing Esc or F10
Go to System Configuration or Advanced settings
Find Action Keys Mode or Fn Key Switch
Set it to Disabled to lock the function keys
Save changes and exit BIOS/UEFI
Use the HP keyboard utility or HP Hotkey support if installed
Update BIOS and keyboard drivers if the Fn lock option is missing