So I was booting Windows 10 from a drive labelled C: and all was well and good.
Then I changed some parts around in my computer. Lo and behold, my computer is still booting the OS on C:, but from an unlabelled UEFI system partition on an external hard drive. Wat.
I checked C:\boot, and there's nothing there. Startup repair does nothing, since it's properly booting after all (from the wrong place).
I need to move this computer around, so leaving it the way it is is not an option. I've tried exporting the system bcd and putting it in C:\boot and marking the partition as active, but the bios still won't recognize the drive as bootable, so I'm assuming my MBR is toast. I'm also pretty sure bootrec is acting on the mysterious external system partition by default when I try to repair the MBR.
I won't ask for a magic solution, since this is a pretty weird situation, but do you have any ideas of things I could try, or tools that would fix the MBR on the correct drive, or restore the stuff that should be in C:\boot by default?