[ubuntu] After Ubuntu upgrade from 14.04 to 16.04, graphics won't work

When I first upgraded, I was given a "system is ruing in low graphics mode" message, then everything ran just fine, graphics apparently normal. When I restarted it some time after, however, after selecting Ubuntu on grub, it gives me a screen that, to my memory (didn't have the time to screencap), seems to imply that something is wrong with the disk, after which it goes blank for a bit, then very briefly shows a bunch of rainbow static combined with a mosaic of my desktop. When I looked the Ubuntu partition over in Windows using DiskInternals Linux Reader, all my files were fine (and yes, I did immediately make a backup).

I reinstalled Ubuntu, taking care to set everything as it was (same mount point, same username, etc.), and this did not fix the problem. When I try Ctrl + Alt + F1 in Ubuntu, the terminal does show up. Here's a screenshot I took of the terminal. http://oi64.tinypic.com/kbrldw.jpg The "lspci" at the bottom was something I tried typing.

While rebooting, I noticed something odd about the Boot Options Menu, namely that there are two options for Ubuntu. I tried them both, and they did the same thing.

I also took this screenshot of something that makes me suspect this is more than a graphics error.
http://tinypic.com/r/del30g/9 Failed to start Load Kernel Modules? Was this because I only allocated about 20 GB to the Ubuntu partition when I first installed? I remember having to restart the upgrade process after cleaning a few things out, but considering that it worked fine until I restarted it after the upgrade, I honestly have no idea what went wrong here.
I tried ruing it in failsafe graphics mode, yet when I tried the "reconfigure graphics" option, regardless whether I picked generic or backed-up, I ended up with the window disappearing for a split second, and nothing happening. Ruing "default" in failsafe just gives me a black screen with the X cursor. I can literally do nothing apart from move the cursor around, and press Ctrl + Alt + F1 to get what I took pictures of above, after which nothing happens no matter what I type, so I have to hold the power button to restart.