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#11
You need a command prompt with admin privileges. The first command prompt you opened did not have admin privileges. The bcdboot command needs to be run in command prompt (or powershell) with admin, "Run as Administrator". The C: drive needs more than just to be an active partition, it also needs the boot files created on it, which is what the bcdboot command does.
Then you need to go into BIOS settings and set disk 2 as the first boot device in the boot priorities list.
Once you actually boot the computer from disk 2, it will get the "system" tag, and then mbr2gpt will work on it.