Suddenly my Xubuntu 20.04 installation went wrong: it boots, but it does not react to keyboard and the mouse pointer is not shown. The taskbar and the start button is visible. With ctr+esc I can activate the start button, but can't enter anything into it's search box.
I tried to replace the screensaver according to this post:
20.04 Mouse click and keyboard unresponsive
But it didn't help.
I can press ctrl+alt+F1...F7 and can change to console, and can shut down or reboot it.
I suspect that the window manager is screwed up somehow.
Is there a way to fix it without reinstalling?