A+: Halting Apps Gone Zombie
You can also shut down an unresponsive application, preferably through the Applications tab of the Task Manager. A program listed as Not Responsive might start working again in a few moments. However, if it does not, select the program, click End Task, and Windows will (eventually) shut down the program.
If you are unable to shut down the program using the Applications tab, you can use the Processes tab’s End Process button to stop the application’s underlying process. For example Microsoft Word is an application, but its underlying process is winword.exe. However, you should use this method only as a last resort. Be careful when ending processes; make sure that you know the correct process name for the application you wish to terminate.
Tip: If you have a lot of problems with unresponsive applications, consider a memory upgrade and check for updates to the application, other applications that are running at the same time, and to Windows itself.