After my issue with the Error 1005 and the launcher, I got a claim from ESO Support that the Repair on the launcher won't work if there is not 85 gigabytes free space on the hard-drive. I had 40 gigabytes.
By that time I had uninstalled the game on the launcher and otherwise made room on the hard-drive so that I had 129 gigabytes free space. The launcher filled the entire hard-drive and then, when 336 megabytes of free space was left, came up with an error message that there was not enough free space left to complete the install. It had gobbled up over 128 gigabytes.
Before all this began, ESO took about 89 gigabytes on my hard-drive.
If I understand ESO Support claim correctly, I would need now about 174 gigabytes free space on the hard-drive to successfully reinstall the game.