Often I cannot perform a soft shutdown or restart. The desktop might sound the console error sound once and then nothing happens. I end up having to use the pushbutton momentary switch, holding it depressed until a shutdown happens. I've had this problem for months. There is no particular discernible cause. The problem is not well correlated with the number or kind of apps that have been run. Typical use: Eclipse IDE, Transmission, Firefox browser, gedit, and occasionally OpenOffice.

What should I check to resolve this problem? I'm thinking of wiping the disk and reinstalling but a little annoyed because I would have to first check the quality of my backup (boring).