This follows up with a new twist to: Ubuntu 14.04 stopped booting suddenly
The situation before the problem cropped up was a little different this time around (for one, I didn't mess around with LightDM beforehand): Late this afternoon/earlier this evening, I tried to install some updates on my system with the Software Updater.
Things seemed to go relatively well in that regard, but I also noticed that I was suddenly unable to open Opera normally as well as Unity failing to return search results for applications. I then rebooted. Wanting to check on things, I decided to go into the Recovery Manager. I then ran fsck
followed by the FailSafe Graphics mode.
Unfortunately, the computer failed to boot, so after about 2 or 3 minutes, I did a hard shutdown (power button), did another file check, and tried to start it normally. That didn't work. After 5 minutes of waiting, I rebooted, and tried to load a previous version of the kernel. That didn't work either.
As with last time, it does appear I can at least boot up the basic console, but the GUI just won't work. I even tried starting LightDM, which ended with the system telling me that it was already active.
So I'm left with an Ubuntu that is virtually totally useless to me, especially because I'm not an expert user. Further complicating things is the fact that I'm not sure how I finally managed to get the system to work again the last time.
So, can anyone offer some help?