I just had a unique OSX experience (for me, at least). An application became unresponsive, so I tried to force-quit it from the Dock. It would not quit. Then I tried to tried it from the force-quit dialog. Nothing. Then I opened the Activity Monitor and tried to quit the process. Again, the application window sat open. Then I pulled out my last trick and attempted to kill the process in Terminal. To my amazement, it just sat there. I tried to shut down, but it timed-out. In the end, I had to shut the Mac down with the power button, the first time in years that I've had to do this. Otherwise, OSX (10.4.7) seemed to be working fine -- I was able to quit all my other running application in an orderly fashion before shutting down. Has anyone else ever experienced this phenomenon? What's the problem, and what's the cure?