So I haven't changed anything significant in my system lately (Mint 15, 64-bit, Cinnamon), but I woke up in the middle of the night to the sound of my hard drive thrashing. There were a ton of error messages, most of which I was too tired to read, and my system was pretty unresponsive, so I powered off.
Now, today, when I boot, I see the GUI login screen as usual, but then nothing works right. I get popups saying that Cinnamon has crashed and is running in fallback mode; indicating that I wish to restart cinnamon does nothing but bring back that prompt. I make it in anyway (to a system that looks nothing like cinnamon, with a menu bar at both the top and bottom of my screen), and my system is still relatively unresponsive. I notice that 2 processes, indicator-datetime-settings and gnome-settings-daemon, are both taking up most of my CPU, and are both using up increasing amounts of memory. Killing the processes just causes them to respawn. (Currently they're together taking up 4 GB of memory, having last been killed 6 minutes ago.) This problem has survived across multiple reboots.
The only thing that changed recently that I can think of is that Daylight Saving Time just ended in the US overnight last night; is there a chance that's related? I also installed stunnel and pan yesterday, but everything worked fine for hours after that.
I'm happy to look at logs or anything to help troubleshoot this, but really I don't even know where to start. Any help would be appreciated. Thanks!