Blank screen after HP bios update

[speedycam]

After a recent  (yesterday) HP updates message I clicked to install updates which included a BIOS update

I now have a blank screen despite doing a BIOS recovery

The unit will turn on and show the HP logo with the boot up roundabout on screen but will not go beyond this point

I got to the BIOS recovery via the WINDOWS/B/POWER BUTTON

I am now stuck as to what to do next

Anyone advise please

[Lil_Boy_Blue]

Hi
Hopefully one of these documents will cover (and solve) your problem...

https://support.hp.com/ca-en/document/c00042629

https://support.hp.com/us-en/document/c02693833

Turn off the computer, and then connect the power cord.
Press and hold the Windows key and the B key at the same time, and then press and hold the power button for 2 to 3 seconds.
Release the Power button but continue pressing the Windows and B keys. You might hear a series of beeps.
The HP BIOS Update screen displays and the recovery begins automatically. Follow any on-screen prompts to continue the startup to complete the recovery.
HP BIOS Update recovery in progress

If the HP BIOS Update screen does not display, repeat the previous steps but press the Windows key and the V key. If the screen still does not display, your computer might not support the feature or there is a hard drive issue. Continue to the next step to install a BIOS recovery file from the HP website.
If the Power light turns off, the Power button was held too long. Repeat the previous steps, making sure to hold the button for only 2 to 3 seconds.

[speedycam]

Thank you for your support but unfortunately it did not resolve the problem

Your first suggestion worked perfectly up until the laptop went to the re start mode when the HP lofo and roundabout appeared on screen for a few seconds at which point the screen blanked out again

Am back to a back lit blank screen 

Thank You

[Lil_Boy_Blue]

Sorry, I have no better alternatives for you other than an F2 diagnostic.

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

AND/OR - Power on your PC, press Esc (repeatedly), then F2 at the prompt.
Choose System Tests (Fast Test does a 4 minute hardware check).
AND/OR
HOW DO I USE DIAGNOSTICS?

[speedycam]

Thank you I got into diagnostics from your advice and all system checks PASSED

However upon checking the firmware management tool whilst I am not really computer savvy it would suggest that the BIOS update failed but the laptop will not revert to the previous version 

I am guessing that the update failure corrupted the previous version

As the laptop is still under warranty I think I have reached the point where HP will have to be involved to resolve the issue 

Thank you again for all your help

Speedycam

[Lil_Boy_Blue]

Prego.

Understood.

There was a time when the BIOS was backed up by a small folder on the C: and used to replace/renew any corrupted BIOS installs.  Unfortunately yours does not seem to have that functionality.