Dist upgrade to 18.04 breaks left & right mouse clicks and shortcut keys

Thank you in advance to anyone who reads this and offers any suggestions that might help.
I have been working for over 3 days to find a solution and not being a ‘power user’ I have no real way of getting around without the mouse. We use this machine to run 2 businesses and are basically dead in the water =(

Our Dell Precision M6800 was happily running ubuntu 17.? for about 1.5 years, and have just done a dist upgrade to 18.04.2. Now I can’t click anything left or right click on either the touchpad or wireless mouse and most of the keyboard shortcuts are broken.

When the ubuntu login screen pops up, mouse clicks work fine, but as soon as I log in they stop.

If I press CTRL + ALT + F1, the login screen reappears and mouse clicks work again, but as soon as I log in again, they stop.

CTRL + ALT + T does not work to open a terminal.
ALT + F2 does not work to open a quick terminal command box.
Basically I can’t get to a terminal window =(

After many hours of frustration trying many different things I walked away for some time, when I came back the screen saver (black screen) had activated, and when I woke it up, then I discovered both these shortcut key commands to open a terminal worked, but still no mouse clicks.
Rebooting the computer repeats the same issues, so I have to wait at least 10 mins for the screen saver to activate to enable the shortcut keys to open a terminal.

The laptop is in a dock that feeds 2 external monitors and a wired keyboard. I disconnected it from the dock and rebooted so it was just running the laptop’s own hardware, no change.

I have spent days researching forums of similar problems others have experienced and tried many of their suggestions including (not necessarily in this order):

  1. Software update to ensure any more changes available are applied
    $ sudo apt-get update $ sudo apt-get upgrade

  2. A suggestion to wake things up
    ALT + CTRL + F6 Sign in ALT + CTRL + F7

  3. Another one
    ALT + CTRL + F1 ALT + CTRL + F8 ALT + CTRL + F7

  4. Tried to update all the drivers to recommendations
    $ sudo ubuntu-drivers autoinstall

  5. Updated video drivers to recommended nvidia 418, blacklisted the nouveau drivers
    $ ubuntu-drivers devices $ sudo apt install nvidia-418 $ sudo bash -c "echo blacklist nouveau > /etc/modprobe.d/blacklist-nvidia-nouveau.conf" $ sudo bash -c "echo options nouveau modeset=0 >> /etc/modprobe.d/blacklist-nvidia-nouveau.conf" $ cat /etc/modprobe.d/blacklist-nvidia-nouveau.conf $ sudo update-initramfs -u

  6. Removed the nvidia video drivers and set it back to nouveau with:
    $ sudo apt install nouveau-firmware $ sudo apt purge nvidia-driver-418 $ sudo apt autoremove $ sudo apt install xserver-xorg-video-nouveau

  7. Reinstall inputattach
    $ sudo apt-get install --reinstall inputattach

  8. Reinstall xserver-xorg-input-all
    $ sudo apt-get --purge autoremove xserver-xorg-input-all && sudo apt-get install xserver-xorg-input-all

  9. remove and reinstate the mouse driver
    $ sudo modprobe -r psmouse
    $ sudo modprobe psmouse proto=imps

  10. Remove the synaptics and install libinput
    $ sudo apt-get update && sudo apt-get --auto-remove purge xserver-xorg-input-synaptics && sudo apt-get install xserver-xorg-input-libinput

Did a reboot after trying each suggestion, nothing made any changes to the problems, only changing the video drivers affected the multi-screen positioning.

Also, I ran:
$ xinput -list
it said my mouse is: id=11
then I ran:
$ xinput -test 11
Then I clicked left, middle & right buttons, it showed:
button press 1 button release 1 button press 2 button release 2 button press 3 button release 3
Seems the clicks are registering.

Also another odd behavior I observed:
if I go: CTRL + ALT + F1 to take me back to the login screen, I then log in (and as mentioned all the mouse clicks work fine there so I can even click the login button!), but when I come back to the desktop, I can see a 2nd mouse pointer.
Only one moves as I move the mouse, and sometimes the other one disappears once the moving pointer enters the screen with the fixed pointer.
The moving pointer is black with a white border, the fixed pointer is white with a black border.
2 things both trying to display the mouse pointer?

There have been no hardware changes or software programs added before the dist upgrade.

The machine has 16GB of RAM and has a nvidia Quadro K4100M video card and an Intel Integrated graphics controller with i915 driver.

I am a terminal novice so happy to try commands to get more info but will need the full command please.

Hoping someone will be able to help, thanks in advance to anyone with some suggestions.