If nothing in there helps, you’re going to need to describe your problem in more detail. Start by telling us – What is upside down? Consider adding a screenshot.
(1) Does this mean you tried everything in the Checklist and nothing helped? Including restarting Anki and restarting your computer?
Since you still didn’t include a screenshot, I guess I’ll try more questions –
(2) Is the entire window upside-down – like in the screenshot – container and all, with title bar at the bottom and everything flipped over? Or are just parts of the window upside-down? Which parts? The menu bar (File-Edit-View…), the navigation bar (Decks-Add-Browse…), the list of decks and counters, the bottom buttons (Get Started…).
(3) When you switch to other screens, like clicking on a deck to open its study page, or clicking on Add/Browse/Stats to open another window – are they upside-down too?
(4) What do you mean by that? How are you switching between virtual desktops? Has this happened before with other apps when you do the same switching?