I just had many problems of increasing severity in rapid succession.
I am not terribly computer literate, so sorry if I don't have much information. I think I'm running 20.04. I can't easily get my system specs though for reasons which will soon become apparent.
The first problem was an inability to open Discord. I would click on the icon and nothing happened. I restarted the machine because I figured I hadn't done that in a bit.
As it was restarting, some errors showed up with memory read errors. I don't remember what the errors looked like, but they included numbers with decreasing powers of 2. However, the machine booted up seemingly normally and I logged in.
After the restart, my second monitor was no longer recognized by the system. It was still getting power, and when I unplugged and replugged it just said no signal. It seems like the monitor can detect being plugged into my graphics card (Nvidia Gigabyte 3060 I think?) on the back of the machine, but the machine doesn't detect the monitor. I tried a few things I found online, one of which was to try a new graphics driver. I went into system settings and saw there were quite a few potential graphics drivers available, so I switched to the newest one. None of this got the second monitor working, though, so I tried restarting again.
I am now unable to log into the machine at all. Whenever I try it goes to a white screen which says a peoblem has occurred and to try again. There is no crash handler or other way to get information on what is wrong that I can see. As a result, I am unable to get better information than what I recall.
Edit: I managed to get into the terminal from the login screen and, after some searching, removed all Nvidia drivers with
sudo apt-get purge nvidia*
This let me log back into the computer properly, but now I don't know what driver to use.