Before buying a programmer, try HP's built-in crisis recovery (though it rarely works for full corruption).
If the BIOS is corrupted and the laptop won't boot, you can create a recovery tool. Create the Drive : Run the downloaded HP BIOS update and select "Create Recovery USB flash drive" Flash the BIOS Insert the USB into the ProBook 640 G2 while it's off. Press and hold the Windows key + B ) and then press the Power button for 2–3 seconds. hp probook 640 g2 bios bin file fixed
Signs and diagnostics of BIOS problems