I've been using Ubuntu Gnome 13.10 for about 2 weeks without issue, but today, after restarting my PC, it got stuck on the Gnome splash screen. I managed to load my login screen by switching to lightDM, but when I login to GNOME I'm greeted by a wallpaperless, ui-less screen, and Cinnamon launches a glitchy/messy fallback mode. I can still boot into Xubuntu just fine, but I'm unable to load Compton or any other graphical effects.
In Xubuntu, video playback works flawlessly on Youtube and in VLC, but SMPlayer fails to load. Trying to launch Steam gives the error, "OpenGL GLX extension not supported by display."
I've been looking around for a couple hours now, and I'm unable to find any solution to my specific problem. The last thing I did before this issue occurred was install the PCSX emulator and add the PCSX2 ppa, but I don't see how that could've caused this whole mess.
One additional bit of information is that I also have an ElementaryOS installation on my machine, which continues to run flawlessly.
My PC is a Haswell i5-4570(HD4600 graphics).
I'm currently using the latest mesa drivers from oibaf ppa.(added a week ago)