Continuous harddrive activity, cpu fan spins up, mouse pointer frozen.
After using my laptop for several days, the hard drive light will suddenly stay on continuously, the cpu fan will spin up, and if I try to move my mouse pointer, it will shutter and then freeze. When this problem happened, I had to hold down the power button and then reboot my laptop.
I noticed I had some time before the mouse pointer would freeze, so I decided the next time this problem happened, I would run fatrace command in the terminal to find out what is cause the hdd activity. I was using Firefox and fatrace showed some Firefox activity. The next thing it showed was writes to xsession logs in my home directory and then it froze.