Reboot and select proper boot device after motherboard battery swap

[radnevr]

Hi all,
I’ve had my novatech laptop for a few years now , I keep regular maintenance of it , clean it and give it a good check every few months, but I’ve encountered my first issue, I hope someone can help as I am lost.

I was repainting my office and disconnected the laptop from the power cable, upon a boot I was greeted with a CMOS Battery message , so I went and bought a new one. Swapped it and rebooted, message is gone now… however I don’t get any boot devices.
I’ve tried everything I can think of, reseated the hard drives , tried to boot from usb Ubuntu , but usb is not an option either . Both my hdd are recognised by the bios in the SATA ports but are not available as boot options.
Any suggestions will be greatly appreciated. I’m attaching only 1 screenshot as I am a new user

[radnevr]

Hi,

Alright, i spend a few more hours and finally figured it out.

When my battery ran out it wiped my NVRAM which held my boot table. Since this is a windows 10 machine it uses GPT …etc for fast boot, so the ID that was inserted in my NVRAM is gone. I had to recreated it by rerunning the bcd file on my partition.

If you insert a recovery disk in your machine and go to command prompt (repair doesn’t work)
write diskpart
once you are in diskpart, be careful… there be dragons here.

you can create a new partition or use the boot partition you already have (only volume that is FAT32 formatted)
you need to run the following

cd /d e:\EFI\Microsoft\Boot
bootrec /fixboot
bcdboot c:\Windows /l en-gb /s e: /f ALL

where
e:/ = your new drive
c:/ = your windows system drive