I can't open the display server or use graphical programs/load desktop environments

[MAFoElffen]

You have tried adding 'nomodeset' to the grub boot line, so it is not your video driver. You have renewed your .Xauthority file, so it is not a permissions problem...

At the Grub Boot Menu, using the same method for editing the Linux Kernel Boot line, adding and trying 'nomodeset'... You could alternately try the boot parameter 'amdgpu.dc=0', then <Cntrl><X> to continue the boot process to see if that helped... But I am thinking, try that next, if that doesn't help, then we need to go on and dig deeper.

The order of installation and connections of is as follows:

• Display Engine (XServer or Wayland),
• If Xserver, then Xinit...
• DM (Display Manager [the graphical login manager]- SDDM. etc.)
• DE (Desktop Environment- Plasma, etc.)

I have a plan. I think the connections between the pieces of might have gotten 'confused'. Each part of this plan, starts from the least invasive to more invasive...

In the first part of the plan, try

sudo dpkg --configure -a

This will try to reconfigure all that is installed... It knows the order it needs to do things, and how. Let it go through everything them. On successful completion, reboot to test... if that does not work, then on to the next step....

Next would try to reconfigure each piece in order

sudo dpkg --configure xorg-xserver
sudo dpkg --configure xinit
sudo dpkg --configure sddm
sudo dpkg --configure plasma-desktop

This does the same as above, but tells it to do it in the order, We are telling it, to those specific packages... On successful completion, reboot and test. If that doesn't work...

What I am thinking,and have seem work, it that if you reinstall the pieces of your graphics layer, in order, then it will reinstall everything needed to get everything reconnected (including the soft and hard links).

What I do not know is the desktops you may have installed...

ls /usr/share/xsessions/

That will list all your installed desktops.

Then do

sudo apt update
sudo apt install --reinstall xorg-xserver xinint
sudo apt install --reinstall sddm
sudo apt install --reinstall plasma-desktop

Which will reinstall XServer, xinit, sddm and plasma.desktop in order... At successful completion, reboot and test.

If at any time, if one of those commands do not complete 'successfully', stop and post the error, and we will go from there to resolve that.

[ash22]

I tried the "sudo dpkg --reconfigure -a" command but got an error that said "--reconfigure" is an unkown option.

I also tried

dpkg-reconfigure -a

but then it just gave another error:

Unknown option: a

So I couldn't try any of those steps

[MAFoElffen]

Dang. My fault on that...

There was a change in the commands between a few versions... And I was in a hurry and had my own typo's there (sorry). My mind was thinking one thing, and fingers typing another. I went back and edited the commands in the previous post for you.

sudo dpkg --configure -a
# OR
sudo dpkg-reconfigure -all

But the later command (dpkg-reconfigure), with the --all flag stopped working sometime around 16.04 LTS... After they changed it.

[ash22]

I get an error from that command too

dpkg: error processing package xorg-xserver (--configure)
No package named 'xorg-xserver' is installed, cannot configure

Would I need to do it on one of the "xserver-xorg-video" packages? Because there are different ones that are installed and I wouldn't know which one to try them on.

[MAFoElffen]

I just checked what is current for Ubuntu... Dang.

Substitute 'xserver-xorg' instead of 'xorg-xserver'

[ash22]

What I got was

dpkg: error processing package xserver-xorg (--configure):
package xserver-xorg is already installed and configured
errors were encountered while processing:
xerver-xorg

[MAFoElffen]

That is only one line from Post #11... Did the other in that same Code block return the same? If they did, then reinstall those individual packages according to the commands in the next Code Block there in that Post...

The idea there was to reconnect any unconnected between them... Starting with the least invasive to more... Even if you reinstall those packages, that does not affect your personal data, installed aplications or the core system.

[ash22]

Did the other in that same Code block return the same?

Yeah, it happened with all of them

[MAFoElffen]

And what happened when you did these?

sudo apt update
sudo apt install --reinstall xorg-xserver xinint
sudo apt install --reinstall sddm
sudo apt install --reinstall plasma-desktop

[ash22]

And what happened when you did these?

sudo apt update
sudo apt install --reinstall xorg-xserver xinint
sudo apt install --reinstall sddm
sudo apt install --reinstall plasma-desktop

They reinstalled but I still couldn't open the xserver