This tutorial provides the steps to kill unresponsive application on Mac OS X Lion. This would be useful when you are facing problem while shutting down Mac because of some unresponsive application. You can kill the application by the option provided as part of the Apple menu.
Click the apple menu and select Force Quit from the menu list
Select the application and click the Force Quit button.
Click Force Quit again to confirm.
Now the Mac system should shutdown without any problem.