Essentially, I was trying to work on a HFS+ disk I have (under W10), so installed Paragon HFS+ to be able to access it. However, unfortunately, I rebooted my computer after installation and got a BSOD -- "Inaccessible boot device." I have since been completely unable to get it to boot into this Windows installation.
I've tried literally everything:
Booting into recovery to try to have it automatically fix it (of course, it didn't work.)
Disabling Paragon HFS+ from the registry
Removing Paragon HFS's registry keys as suggested by one of the few other people on the internet who has had this problem (to no effect)
Recreating my EFI partition
A variety of different SATA plugs on my motherboard
Booting into another OS (works! but not the solution)
Mucking about with bootrec / etc. in the recovery command line from the installation media
Changing the boot order of my drives (and unplugging all but the Windows 10 one)
Ensuring with diskpart that the drives are assigned the correct lettering
... with no luck. I've checked the files on the drive, and everything is intact. I've recreated the EFI partition and the MBR, and both methods of booting get to the loading screen, spin for a bit, then give the same BSOD.
I cannot feasibly reinstall this drive's copy of Windows at the moment, so must somehow get this installation working again.
Is there any way to manually remove Paragon HFS+ from the installation via another installation of Windows on a different drive? I've tried WMIC but that doesn't seem to work, or even theoretically allow me to target a different drive.
Or, conversely, is Paragon even the problem? According to https://www.reddit.com/r/techsupport/comments/36ies0/inaccessible_boot_device_after_uninstalling_hfs/ , it's been known to cause this issue...
Is there any way I can salvage this? The installation is there, it gets to the loading screen, the drive is fine, all of the necessary files are there, the program I thought could be the issue is functionally disabled... I truly have no clue what the issue could be.
12GB Ram (tested functional -- not the issue)
Gigabyte GTX 760
120gb solid-state drive with the broken Windows 10 install, and an EFI partition to boot it from.
2TB drive with data
1TB drive with data and a OSX Yosemite installation