Here is another way to try to get to Safe Mode.
Boot to the Command Prompt of your boot disk ). Enter these BOLD commands and press ENTER after each.
(Note the colon after C with no space; then the spaces which are important - one after T before / & T before { & } before B & Y before L)
C:
BCDEDIT /SET {DEFAULT} BOOTMENUPOLICY LEGACY
EXIT
You are back to the boot screen -> Shutdown the computer.
Boot back up and "immediately" start tapping F8 (That means power button - then F8).
Hopefully that should get you into Safe Mode.
--------------------------------------------------------------------------------------
To reverse that you can use the same steps and type these (again note spaces)
C:
BCDEDIT /SET {DEFAULT} BOOTMENUPOLICY STANDARD
Restart but F8 will not work now.
if you can get into safe mode, I would roll back previous update or run
right click start button
choose powershell (admin)
copy/paste this command into window:
Repair-WindowsImage -Online -RestoreHealth
and press enter
Then type SFC /scannow
and press enter
Restart PC if SFC fixes any files as some fixes require a restart to be implemented
First command repairs the files SFC uses to clean files, and SFC fixes system files