HELP my Ubuntu notebook has crashed!

It’s on a black screen with white writing/codes and I cannot get it to boot up! What can I do guys?

If you turn on the PC, then immediately hit and hold the Shift key … does the PC boot to the GRUB screen ?

Well I can’t shut it off by pressing the power on/off button, so what should I do Mark?

Press the power button and hold it down until the PC shuts down

Ok finally got it shut down.

I just did what you said with the shift key and it took a few tries to get it to come on and it has a black screen with a red box saying:

secure boot violation
invalid signature detected. check secure boot policy in set up.
and there is an ok button.
I have not clicked on it as dunno what to do next nor understand what this all means.

Enter the BIOS and disable secure boot.

You can “probably” get there by hitting the OK button.

The only way was to hit return now it briefly went to to a purple screen and now a black one with white writing saying stuff I don’t understand which I typed already in the other thread we were on:

BUT!! I just tried to boot up the notebook and it goes to a black screen with writing on it. Too much of it to type up but it says things like:

couldn’t get size 0x00000000000000

Kernel panic- not synching UFS: Unable to mount root fs on unknown -block (0,0)

I am just about to have my dinner, so will be back later Mark. I hope it hasn’t had a big nasty crash and died!

Turn off the PC

Turn on the PC and immediately hit and hold the F2 button

did the PC enter the BIOS settings screen ?

Ok, that took some doing to make it come on! I can hear something clicking every time I press that power button.
There is a pale blue screen that says:
Aptio setup utility
Main Bios information
and then lots of other stuff on it. Is this what you meant?

Yes…

Can you see a tab labelled “Security” ?

Yes it is there.

Click it…

Then look for a setting labelled “Secure Boot menu” (it may be at the bottom, so you may need to scroll) … set that to “disabled”.

Ok done that Mark. I am worried! I hope the HD has not corrupted! It was working perfectly last night.

Is there anything onscreen that tells you how to save the settings, and exit ?

Yes, F10. I presume I should press F10 next?

Yes press F10

What happened ?

Did it save and reboot, or just save ?

it went for a few secs to a purple screen and then back to the black screen with white writing which says :
couldn’t get size 0000000000000000000
Kernel panic
and tons of letters and numbers which would take ages to type up

Okay you need to access the GRUB menu

Turn off the PC

Turn on the PC

and immediately start stabbing away at the Shift key … are you eventually presented with the GRUB menu ?

It take pressing and pressing many times to even make it come on, and when it does as soon as I hit shift it just powers off.