Question HP4540S cant get to BIOS; lost forever?

[Tanyalin]

Hello, I was given an old HP4540S single boot only Ubuntu 19.04 (I don't know Linux). End story I tried to add partitions to install Windows on one and 20.04 Ubuntu on the other (fascinated with learning Linux). Well I accidentally deleted the /dev/sda where the OS was mounted. At one point I was told to reboot. HUGE MISTAKE.
I cannot get to BIOS to install the bootable Windows...it doesn't detect the CD....I tried everything suggested to get the F keys to work; and keyboard dies not have FN key. HP wouldn't help.
Is there any way to get to the BIOS at this point?
If not; what do I need to replace in order to get this working again?
A processor?
I know just enough to be deadly...obviously...but I won't give up.
Would someone please point me towards the next step? I miss my computer!
TIA!!!

 

[kappa_800]

I don't understand you completely. I get that you deleted /dev/sda (which is the hard disk and not a partition on that hard disk).

So I guess you want to get into BIOS at this point.

 

[Tanyalin]

I don't understand you completely. I get that you deleted /dev/sda (which is the hard disk and not a partition on that hard disk).

So I guess you want to get into BIOS at this point.

Yes. My function keys aren't working to get me there. I have tried all ways to restore the F keys.

I contacted HP about other way to get into BIOS and they couldn't help me...

 

[kappa_800]

Have you tried connecting an external usb keyboard to your laptop to see if it works?