Sorry for the delay. (I had a doctor's appointment for a blood test).
Double-click the icon for your C drive.
Then double-click each of the following in turn. (You'll encounter 'You not have permission' messages but simply click 'Continue' in each case):
Windows
System32
config
systemprofile
Right-click underneath the list of files/folders and select New > Folder. Call your new folder 'Desktop'.
If you can't restart, it's time for some brute force:
Remove the power lead (if relevant). Remove the battery. Wait for a minute. Replace the battery (and power lead, if required). Power up again.
I am now using my computer. It wouldn't let me rename the AppData file. I just switched off and eventually got some icons back on the Desktop but something has gone wrong in that when I click on Microsoft Edge for example it says explorer. exe. Class not registered.
...and the text is not 'right' on here, it looks fractured.
...but I have my computer up and running and say a great big thank you to you, Buen for your patience and skill and to all the others who have tried to help me today.
I'm still having problems. Although I now have a desktop of some sort, my start button doesn't work and I can send emails because, for some reason, my 'at' symbol won't type. I get this..." instead.
Think I would have taken a different route Tills. I asked the questions with a view to effecting a safe boot and possible reset to a previous point or the deletion of a recent update that was obviously corrupted. The route that you undertook was in the list of possible measures to take but down the list a way. It was all available to read up online as well. You really should have had an stick with the os loaded just in case of such an event .....we all should.....I have 3. One for each machine that I run. Strange thing is that this morning I was a little preoccupied. There was an attempt by someone to gain access to my desktop using a Trojan malware programme. Rather a nasty one, and I was sorting that out and running the scans. Well done defender. No drama.