If you power on your laptop HP Elitebook 840 G1 or G2 and you get an error message No Bootable Image Found, No Bootable device found or similar, that could mean you hard drive is faulty or you need to change your BIOS Boot settings depending on the type of system you have installed.
Link: Test the hard drive using HP Hardware Diagnostics
If the hard drive tests successfully the next step is checking how the BIOS Boot Mode is set up and confirm the correct option is selected. Please follow the below steps:
- Turn on or restart the computer.
- Immediately, press the Esc key (Pressing Esc displays the startup menu).
- Press F10 to enter the BIOS Setup.
- Select the Advanced tab.
- Select Boot Options.
- Scroll down until you see Boot Mode and then select UEFI Hybrid (With CSM) as this will provide both legacy and UEFI compatibility.
- Click Accept and then Save.
- Restart the laptop when done. Save again if asked for.
If you confirm your hard drive is healthy and changing the BIOS settings doesn’t solve the issue then you might need to try to reset your OS as it might be corrupt.
Link: HP PCs – Resetting Your Computer (Windows 10)