Startup BSOD Oxc000021a

Hi everyone,

A newbie here, I had my bacon saved once from the 8 forums and now I am looking to see if you could please work your magic again.

I am receiving the error message above upon booting. It started after windows was updating to the last update.

So far I have tried:
1. Booting into safe mode
2. Booting with driver signatures withheld
3. Refreshing the PC with files/settings in place (this failed after about 10 minutes...it is unclear whether or not any failes were deleted or changed)

All 3 have failed.

I have also from windows pe:
run DISM /revertactions (failed)
run DISM scanhealth ( with result being files are corrupted after scanning 5%)
run DISM checkhealth (it says the installation is repairable)
run DISM restorehealth (it gives me an Error 1372 stating files are corrupted)
saved the registry SOFTWARE and SYSTEM keys and used the backup keys
SFC /scannow fails with a message about some operations not being able to be completed in the Win PE environment
I am running these DISM commands using as a source a brand new USB made by Windows Media Creation Tool

Is there any thing else I can do or try? I am at my wits' end.

Any help would be appreciated. Unfortunately I have been using windows file by file backup (rather than system image) to back up my entired computer (3 drives and a total of about 800gigabytes of information) and it looks from what I have read it will be a nightmare to try to recover using this method.

I didn't make any specific restore points, but I do not remember disabling system restore feature. However, when I tried to do a system restore, i got a message saying that it couldn't find any!