Firstly, PXE is network boot so you may want to play with boot sequence in your BIOS / (U)EFI control panel if you don't regularly boot from a network source - it's an unnecessary delay in turning on your computer if you don't use it.
As for the grub error, also very interesting. i386 is for non-EFI 32bit computers, and Zorin's Ubuntu base doesn't officially support 32bit machines any more. If your grub worked preivously then you shouldn't have a similarly cursed device as I do, running 32bit (U)EFI despite having a 64bit CPU. I'm guessing that the power cut either corrupted your HDD or at least the parts of it needed for (U)EFI or grub.
You will need to manually boot into Zorin and reinstall grub, I believe.
Boot Into Zorin
- Use Super Grub2 Disk from a USB stick
- (I recommend flashing Ventoy and keeping some handy tools to hand, like GParted and CloneZilla and a couple of linux ISOs as well as SG2D)
- Manually boot from the grub rescue shell
(if neither work to boot into your installed Zorin OS, it may be very corrupted or damaged from the power failure, so use a live environment to try and mount the partition to rescue important data before reinstalling Zorin completely, unless someone more knowledgeable and skilled than I am has a better option)
Repair / Reinstall Grub
Once in Zorin, not from the live ISO, open a terminal and run these commands one-by-one:
sudo apt install os-prober efibootmgr
sudo grub-mkconfig -o /boot/grub/grub.cfg
sudo update-grub
Alternatively, if the above didn't work after rebooting, get back into Zorin again and then try:
sudo grub-install /dev/sdX # where X is the drive Zorin is installed on, e.g. sda, sdb
sudo update-grub