Boot device not found. Please install an operating system on your hard disk

[Wesdjulian]

When I turned on my computer  it says boot disk not found. Please install an operating system on your hard disk. Hard disk 3fo

[BeemerBiker]

Boot device not found: Either the disk is defective or the OS startup needs to be repaired: Watch this video.


Tap the ESC key after powering on. Tap it once a second after you see the LEDs on the keyboard flash. When you see the startup menu, press F2 to run diagnostics. Make sure that the memory and disk drive diagnostics pass.
If a component fails during the UEFI test then Click here to check warranty
Lookup any of the 24 character Diagnostic error codes here.

If disk fails it needs to be replaced.

if the disk passed diagnostics then
The BIOS may not be configured correctly to boot

• Go into the BIOS setup.
• Press F9 and any option that sets defaults on every menu of the BIOS.
• Ensure secure boot is enabled and the date and time are correct.
• If there is a boot option for UEFI chose UEFI
• Save settings when exiting.

Here is HP's official guide

https://support.hp.com/us-en/document/ish_3053911-2842957-16