I have tried to install the 1903 Win10 (Home) update on my PC. After a while it said that a restart was needed so I did that. Now it won't complete the set-up process and I can't boot the PC.
During boot the windows logo appears, then is replaced by a black screen with a spinning icon.
This basically stays forever. Although I get the occasional indication of disk activity (once every 2 seconds or so), the PC appears to be doing nothing. It is running very quietly and not generating any noise or heat.
I have booted from a Win10 installation disk into the advanced recovery options, but nothing here works. I just get errors.
It does not find any recovery partition. System restore says "you must specify which installation to restore" (but I have no options) Start-up repair says "could not repair your PC" Uninstall feature updates says "We ran into a problem"
Via command prompt them sfc /scannow shows no errors bootrec.exe /fixmbr says "completed sucessfully" bootrec.exe /fixboot says "access denied" bootrec.exe /rebuildbcd shows me an option  c:\windows I say "Y" and then it says "The requested system device cannot be found"
I am at a loss on how to fix this problem other than wiping the disk and starting again, which I am reluctant to do and it will take me ages to restore all my data.
Any ideas? What can I do?