Ged
Thank you. But
I have run the CC cleaner tool and am now trying to re-install the various programs.
It seems stuck at

The error message I saw previously still pops up

And in AppData\Roaming\Adobe
I can see 3 instances of Photoshop present

The cleaner does not seem to have done a good cleaning job.
Velson
First of all, the folder AppData\Roaming\Adobe is not the installed program files. These are your preferences/settings/configuration, located in your user account. If these folders are deleted, which they can, the application is still installed, but it removes the settings and reverts the application to to clean factory state. The installed program files are not here, but in the main folder "Program Files".
Sign out of the CC desktop app and sign back in. This forces a rescan of all installed applications.
Then go here:
