I was impatiently changing docks from plank to cairo-dock to docky. Eventually plank kept turning up so I purged it; the impatience bit meant that I didn't scan what else would be uninstalled or purged. The end result is the login splash screen is fine, and password is accepted, but there's no wingpanel no dock just the wallpaper. I tried using terminal to do all updates and upgrades hoping the missing bits would be re-installed but I was wrong. Pantheon is the latest it's a problem with gtk or access to filesystems I have ruined. Any help appreciated. I can be more specific - I hope - if someone asks me for specific info. Thanks for having this Forum. Michael.