INACCESSIBLE_BOOT_DEVICE error when booting Windows 8.1

I installed LabVIEW and after restart, my system started crashing with DRIVER_POWER_STATE_FAILURE error. And I have no restoration points.
I booted into safe mode, ran sfc /scannow and dism /online /cleanup-image /restorehealth.
They "fixed" something and now I can't even boot into safe mode, both normal mode and safe mode crash with INACCESSIBLE_BOOT_DEVICE error.
Then I ran bootrec /scanos from recovery menu just to be sure boot files are intact.
It returned:

Total identified Windows installations: 0

To restore boot files, I ran

diskpart  
sel disk 0 
select volume 2  
assign letter m:
exit
cd /d m:\efi\microsoft\boot\  
bootrec /fixboot  
attrib BCD -s -h -r  
ren BCD BCD.bak  
bcdboot C:\Windows /l en-us /s M: /f ALL

This made things even worse: now when I'm trying to boot into recovery, it crashes with 0xc0000001 error. Normal boot still crashes with INACCESSIBLE_BOOT_DEVICE error. Now I can only do something from a bootable usb stick with Windows 8.1 installer.
What's weird, boot fixing utility correctly identifies the installation but fails to fix anything. SrtTrail.txt says

Startup Repair has tried several times but still cannot determine the cause of the problem.

Since sfc /scannow doesn't work anymore, tried to run

sfc /scannow /offbootdir = c:\ /offwindir=c:\windows\

It completed successfully and didn't find any errors. So did

dism /image:C:\ /cleanup-image /restorehealth

Also when I run bcdedit, it shows both boot manager and boot loader while bootrec /scanos shows zero.

I suspect, this may have something to do with GUIDs but I'm not sure what value should they have.
What else I can try to make Windows work? My PC has UEFI and Windows is installed on GPT partition.