Not fixed yet and the issue is costing me £48 to resolve. I hope you can fix yours for free Rod, although time is money as far as I am concerned. So I decided to use Dell support to help me wipe my hard drive and reinstall Windows 10. They believe that is the only solution. I expect the drive will need to be reformatted and then a fresh installation done. Thank you Microsoft for effectively installing Ransom Ware on my Dell PC…
After reading the link Martyn provided: "There’s a thread running on answers.microsoft.com3 which looks like a close match for these problems. Search for “Windows 10: Update 1803 failed - leaves laptop machine unusable”. I’m not sure I fully understand it but it sounds like the update may trash a machine with an old installation in which the system reserved partition is too small."
and after reading comments from Win 10 users who had spent days trying to resolve the same issue as Rod and I have, I rang Dell. The all in one PC I have is less than a year old and under warranty, however the software isn’t. I suspect the Win 10 operating system may have been installed on a small partition when the PC was manufactured and because of that it was unable to process the Win 10 1803 update making the PC unbootable as was suggested by Martyn.
My problem is I don’t have a Win 10 recovery DVD as Win 10 was preinstalled at the Dell factory - I’m not fully conversant with boot up processes but the machine is not using the old style BIOS but boots by a process called UEFI (Unified Extensible Firmware Interface) so the machine will not as it stands be made to read anything from its DVD drive. Hence my call to Dell. I now have a download from them of Win 10 on a DVD-R disk ready for installation tomorrow at around 1.00pm, when I have a up to a 2 hour telephone appointment slot with their software engineer on the phone to restore my machine to a working condition (I hope).
There will be the usual software packages to reload after that, but fortunately all can go back on at no additional financial cost to me, just time.
So I warn anyone reading this you will probably be lucky installing this update, but you may not be and it could cost you money and time fixing it, so be aware.
Thank you Martyn and Rod for the pointers in resolving my issue, hopefully by tomorrow
evening I can report back to confirm that I have a functioning Dell PC.