Cannot boot Ubuntu, nor enter in the BIOS

[Tartopinto]

Due to an update process went wrong, I accidentally deleted some important packages of my Ubuntu system (unfortunately I cannot remember the names, except for Mutter). When I did the screen went immediately black. Those packages were all the Unofficial software packages not provided by Ubuntu on my system.

Now, when I try to switch on the machine the following happen:
1) blanck screen
2) splash screen with (from top to bottom): Hp logo, this phrase "protected by HP Wolf security", a loading sign and  the Ubuntu logo.
3) The screen goes blanck forever

My aim is to restore enough Ubuntu packages to be able to interact again with the sytem. I tried to enter the BIOS to either use GRUB command line or to change the boot order to an external USB key. Unfortunately I am unable to do that.

Things I tried to get into BIOS:
- press repeadetly ESC/F2/F10/F12 after switching the workstation ON (with and without the Fn key of the keyboard)
- long press ESC/F2/F10/F12 
- pressing all F button alternatively
Nothings seemed to have any effect at all.

Weird facts to notice:
- after a certain amount of time, pressing ESC makes the workstation beep. If I long press it beeps with a frequency of 1 per second, otherwise when I press ESC two times.
- repeteadly pressing F10 results, after a while, in a single beep (after which nothing happens anymore)

My Workstation came with Ubuntu preinstalled. Might it be that I deleted some packages installed by HP that were essential to boot the machine? Is HP wolf security involved?

Specs of the machine: HP Z2 G9 i9-13900K/2x32GB/1TB SSD/8TB HDD T400 Linux Ubuntu

Please, any help is very well appreciated, I do not know what to try anymore...

P.S I read on another post that a problem might be that the Nvidia graphic card is preventing the display of the BIOS. Problem is that I only have two display ports (tried with both) and I do not know how to connect the monitor to the motherboard directly...

[Tartopinto · Accepted solution]

Thank you all, I managed to solve the issue!

For future reference, here are the steps towards the solution:

• I realised the machine was going into the BIOS, but nothing was visualised on the screen. I did it by looking at the layout of the BIOS interface on the web, and then blindly trying to boot Ubuntu from a USB key.
• I suspected the problem was that the graphic signal was not being sent to the DPI ports of the motherboard
• I connected the screen directly to the NVIDIA Graphic card (I had to find an adaptor since it only had micro-DPI ports that I did not notice before)
• I booted into Ubuntu, from where I noticed the graphical interface was missing. I used the terminal instead.
• I looked for the packages I had uninstalled on /var/log/dpkg.log
• I reinstalled everything
• The problem was (probably) that I uninstalled some HP drivers (oem-stella-meta, oem-stella-aron-meta oem-stella-factory-meta) that had ubuntu-desktop between its dependencies. This resulted in it being uninstalled.