I've tried asking on the Ubuntu forums in this thread but they stopped responding. I cannot open the display manager, use graphical programs or use a desktop environment. Before it happened I suspended the Network Manager service which needed a root password because I was testing something. The next time I booted into Linux, I couldn't login to any desktop environments I have installed. I can only get to the SDDM login screen and I have to use ctrl+alt+F2 and use the tty to do things.

I have tried to troubleshoot this for 4 days and none of the solutions work. All of their solutions work for a different type of problem. Their graphics not displaying had something to do with SSH which I'm not doing, my computer is a normal desktop computer. When I echo the $DISPLAY variable, it's empty ('''') unless I export 0.0. xhost + fixed it for most people that have my problem, but it doesn't work. I just get
But when I start X with superuser privelleges, it actually starts up. I don't know why I'm getting this message or what it was that was changed.

So is it your personal login? If so I may have a solution.

Are all the files and directories in your homedir owned by your username?

what do the logs say?
Check in /var/log, the Xorg.0.log, messages, or syslog files should have an error message that can point to the problem.

Try creating a new user and see if they can log in, if so then the issue is with the current user, else it could be a different issue.

I wonder if you have inadvertently transferred your X authentication file to the ownership of root. If so, you will no longer be able to access it as an unprivileged user. You say you had to do something as root and that started the problem. How did you become root? Did you use gksu or sudo or su? gksu and similar programs are supposed to protect your environment from root so that this can't happen, but sudo and su usually leave you in the same environment.

Try deleting .Xauthority at the console, then logging in again

the most important thing is to post what you have tried exactly and the respond you got exactly.
Telling "it doesn't work" or dropping in a single line from the error message is not enough. Also telling us you found something in dmesg is insufficient. Most probably post #5 is correct.
You can try to create a new user and try X with that - without root.

Deleting Xauthority file and creating a new one and using chmod 600 on it didn't fix it. When I read the message after startx fails, the log file goes to xorg.1.log rather than xorg.0.log.

For the log file, should I just copy it to a txt file and attatch it to a post?

I opened the system monitor (Ksysguard) and suspended Network Manager. I was prompted for the root password to suspend it.

Xorg.1.log is for the X server on display 1. If you don't have multiple displays, then something is wrong in your configuration.

You can grep for lines starting with EE and post them.

Edit: most likely you have started 2 X servers, so the second one is logging to 1.
See https://askubuntu.com/q/951260/1030912

1 members found this post helpful.

Delete it and do not create a new one. Creating an Xauthority file is for the system to do, not the user.

These are the Xorg logs. I only use one monitor so there shouldn't be two of them.

Attached Files

	Xorg.0.log (49.7 KB, 8 views)
	Xorg.1.log (32.3 KB, 8 views)

Right; a new one gets created when the X server starts a second time. One thing you may try is by logging in (on a terminal) as your 'regular' user, and deleting the Xorg log files like the ones you noted here, along with any files in the the $HOME/.local/share/xorg directory. Had a nagging X issue, and just removing those log files and typing in "startx" brought things up.

Looking at the Xorg.1.log I see entries stating that all of the ati, vesa and fbdev modules failed to load. That could be what is causing the issue. You can try installing xf86-video-fbdev or xf86-video-vesa . (Not sure about the package for ati)

Fbdev and vesa are crude, unaccelerated, fallback drivers. Installing them is optional. When not installed, they cannot be loaded. As long as an optimal driver is loaded and working properly, their failure to load is a non-issue. Their most significant use is to enable any X at all for the purpose of diagnosis and/or reconfiguration, to get X working the way it's supposed to work using KMS-supported drivers modesetting, amdgpu, intel, nouveau, and several others for uncommon GPUs. Ati is not an actual driver, but a driver selector, available for determining which among 3 old drivers to load for ancient ATI GPUs. Optimal driver for OP's CPU is most likely the amdgpu DDX display driver, with competent fallback to modesetting DIX display driver if the amdgpu is not available.

Thanks for the clarification and details. I will try to do a bit more research over the next few days to learn more about this topic as I now know that I need to learn a lot more