Hi
https://support.hp.com/us-en/document/bph07107
Hardware | 3.4 | The Main-Board displays a power failure (crowbar).* Indicates potential power system failure. | 1 Reduce to minimum config (CPU, Main-Board, PSU, Single memory DIMM) and isolate failed component. 2 Reduce further if issue persists. 3 Test known good PSU. 4 Replace affected component. 5 If unable to confirm source, replace CPU, Main-Board, PSU. |
First:- Turn off the computer, press and hold the PWR button for 4 seconds.
Then - Leave only keyboard and mouse connected, disconnect all externally connected
devices such as Docking Station, USB storage devices, displays, and printers.
Unplug the AC adapter from the computer.
Next - Press and Hold the Power button for 15 seconds to Hard Reset.
Rinse and Repeat
Power on your PC, press Esc (repeatedly), then F2 at the prompt.
Choose System Tests (Fast Test does a 4 minute hardware check).