I can login. I was previously unable to click on the 'next' button on the 'welcome to 18.04' splash after login to finally get that off of my screen. But now I can't do anything.
My USB mouse cursor moves, but no buttons work; left, middle, right. I have tried two different mice(?) but still no joy. The left button works fine on the login purple screen, but then it no long works on the desktop. I have (login settings) tried both the GNOME on Xorg, an the Ubuntu, but both have the same problem - buttons don't work!
Looking at other suggestions on other answers, I did
sudo ubuntu-drivers autoinstall but no joy. I also do
sudo apt update and
upgrade, but no joy.
I'm able to login to the computer that has the problem via ssh from another system that is running 17.10.
So my 18.04 computer is totally down and unable to be used. How can I debug/fix this?