Change boot back from efi to mbr

Most UEFI computers will only boot in UEFI mode from FAT32 partitions. Your motherboard, apparently, does not have that limitation. I am not sure if the "Failure when attempting to copy boot files" is due to the fact that you are attempting to set up UEFI booting (with the /f ALL option) on the NTFS partition with the OS or if there is some other problem.

The standard layout for UEFI booting is to have a small, FAT32 EFI System at the front of the drive that the computer boots from.

One possible solution would be to install Macrium Reflect Free:
Macrium Software | Macrium Reflect Free

Run it and create a Macrium Reflect rescue USB flash drive. Boot the computer from the flash drive and then under the restore menu will be a utility to Fix Windows Boot problems. Run that utility and see what bootable partitions it finds and run the option to repair it.

The other option would be to shrink C: drive partition to create 100 MB free space to create a FAT32 EFI System partition in, then try to write the boot files to it using the bcdboot command.

Ahh, that was a stupid mistake from me, forgot to run it as admin. But I still get the same problem as before, the C: drive does not show up as a bootable drive.

- - - Updated - - -

Thanks for the awnser NavyLCDR. Don't have the time to try the solution you have sugested this weekend so will try it out next week.