Windows error 0xc000000e after running Memtest86, unbootable, cannot repair

[needhelp111111]

I recently reformatted my PC.

Since then I had started randomly experiencing memory usage spikes, to the point where the PC would become unusable. I figured I might have damaged the RAM, so I ran Windows Diagnostic and it found no problems.

When looking at the logs in the Event Manager, I noticed that the memory usage spikes were happening around the same time a group of errors were detected. If I remember correctly, this thing called something like CLSID was being prevented from running because it lacked permission(s). I found a tutorial online to fix this which suggested modifying the ownership of certain RegEdit entries to Administrators and then granting it full control.

Since I was still concerned that some of my RAM might be going haywire, I downloaded Memtest86 and ran it until completion. After pressing escape to reboot the PC, I ended up encountering a blue 'Windows Recovery' screen with the error code '0xc000000e' which supposedly means either something is wrong with the boot record or a required device is inaccessible.

• 
  I tried executing 'Startup Repair' via the Windows installation media, but it responds with a vague error that states 'Startup Repair couldn't repair your PC'.
  
  I also tried the 'Reset this PC' option while selecting 'Keep my files', which throws the error 'The drive where Windows is installed is locked. Unlock the drive and try again.'
  
  I tried 'Go back to the previous build' which states 'We ran into a problem and won't be able to take you back to the previous build. Try resetting your current build instead (Troubleshoot > Reset this PC).'
  
  I tried 'System Restore' which throws the error 'To use System Restore, you must specify which Windows installation to restore. Restart this computer, select an operating system, and then select System Restore.' However, I am never given the option to select an operating system and I am not even dual booting...
  
  Via command prompt I also ran 'chkdsk /r' which did not fix the issue.
  
  I tried running all of the 'bootrec.exe' commands and all of them were completed successfully except '/rebuildbcd' which threw the error 'The requested system device cannot be found.'
  
  I just tried running 'sfc /scannow' and, although the verification phase completed, it is saying 'Windows Resources Protection could not perform the required operation.'
  
  I am thinking of maybe replacing the SATA cable.

Other than that, I am not sure what to do at this point. I have months of work on that drive, which I had not yet copied to my other drives as a backup, so I do not want to reformat the drive entirely.

Does anybody know what's happening to my PC OR how to fix this?

 

[needhelp111111]

I believe I fixed the issue by switching from UEFI/Legacy to UEFI and choosing Windows Boot Manager to boot into. I'm now back in Windows. I'm just wondering why none of my drives are explicitly listed in UEFI mode??