Win 10 update 1803 refuses to finish

I have a HP Pavilion 15-AB223C1 since 2015 and have not had an update problem until yesterday. That 1803 update - which you cannot turn off, refuse, or even review - will not complete. At first we were able to get to the log in screen and when trying to open it gave some error msg about SDS or SNS (cannot remember exactly). Today cannot even get to a log in screen it just starts up with the built in repair console first wanting to you select keyboard layout language, and then you get to all the options. NONE of these options will work - Rollback states there are no restore points with a big red X (there were plenty of restore points prior to update taking control, and I and many others have suffered the case of missing restore points). I tried every other repair console option to no avail.

Finally I decided I will probably have to do a clean repair from a Windows downloaded ISO media. I loaded up both a USB stick and then also burned an image to DVD of the latest on-line Win 10.

I have fiddled with the UEFI trying to figure out how I can stop it from going to the HD (no way to remove a boot i see). I tried separately setting the USB mem stick and the internal DVD to number one boot priority and it thinks for a while (I can see the USB mem stick light flashing, unfortunately when trying DVD there is no light but I can hear it turning) and every time it announces that "It looks like you started an upgrade, remove the media and click yes. IF you want to perform a clean install instead click NO" (see attached) Well I do not want a FRESH INSTALL I want to preserve the thousands of photos on the C: drive and am hoping to get to the position of ISO Repair.

BUT the machine comes back to the build in repair console with the same old list of options none of which work. IT refuses to boot to the USB or DVD and instead returns you to the uncompleted upgrate. WHAT TO DO??

Should I be selecting NO and I want a fresh install and then hope that the screen comes up from the ISO image that will allow me to REPAIR and saving all personal data. I REALLY DO NOT WANT A RAW INSTALL.

I will reserve my caustic comments about Win10 for another time and place. I have attached a screen shot of the message it always returns to.

I think the 1803 upgrade is stuck never having finished and the machine will not allow any other operation. I have no clue how to stop the 1803 upgrade since Rollback and restore do NOT work. (why is restore now called ROLLBACK - at first I thought it meant rollback to Win 8)? ANY SUGGESTIONS.

Looks like the situation reported above is linked to Sihost hard error; also, explorer hard error. Many people (including myself) have reported these catastrophic errors over the last two to three weeks. These error conditions arose at restart immediately after Window 10 April / May update. (I posted my attempts to recover the PC elsewhere in TenForums - please search under sihost hard error.)

As far as I can gather no one has yet posted a workable procedure to make the PC work again.

I downloaded the installation media into a USB (using another working Windows 10 laptop) about a week ago.
But did not try to boot from this USB; why? because I have seen comments by others who reported further problems when trying to apply normal methods of booting from the USB.

Regarding the installation media download: this was done for me 'remotely' by a member of Windows Support Team - interestingly, that person was careful enough to select a previous version of Windows 10 update (Jan / Feb 2018). So, if I do apply this installation media, then I will avoid the option to 'get the latest Windows 10 updates' (during the installation process). Otherwise, I might end up back at 'square one' with the troublesome April Update.

With due respect to good intentioned people who offer solutions, I suggest we need to hear from a person who actually got the PC working after this disaster.

I am leaving a message to 'Brink" and others who promote Window 10 April update: Please warn your readers of the problems faced by some users who applied this update.