[C:…systemprofileDesktop is not available after Win 10 1803 update]

Good day
I have this problem after an automatic update to Windows 10 1803 - on 22nd May
“C:…systemprofileDesktop is not available” and an empty desktop 
Now I cannot get into my laptop at all.
Problem is on Toshiba Satellite L75D A7283 AMD A4 quad core
Reading various forums it seems that I need to download Windows 10 (possibly 1709) and try to install it
Currently using to post this question an old working Vista laptop with an external hard disk.
I have down loaded on to this old pc, Windows ISO downloader via your site but do not know what to do next. I am not sure that Windows 10 has downloaded or simply the exe file

Am I heading in the right direction and if so can you tell me how to get the Windows 10 onto the hard disk ?
Thank you  Mrq