To stop a program that is running that does not respond to any keyboard command you will need to force the program to quit (known as 'Force Quit'). Here is how:

1. If possible, save, and close any open files and/or programs on your system in the usual way leaving only the 'problem program'. This will help reduce the possibility of data loss.

2. Press the 'Ctrl', 'Alt', and 'Delete' keys on your computer at the same time. Select 'Task Manager' from the list of options shown. (Alternatively, you can often right-click the Taskbar and select 'Task Manager' from the pop-up menu that appears then)

3. The Windows Task Manager will now open and show you all the currently running programs on your system.

4. Select the program you wish to stop running on the Programs tab (see below also) and click 'End Task'.

5. Now click the close button 'X' on the top right of the Windows Task Manager window.

Important Notes:

  • Force quitting a program will result in the loss of any files that are open and associated with that program. 
  • Do not confuse Task Manager with Task Scheduler - they are different functions and do very different things.
  • Applications that are not visible on screen are probably not listed under the Programs tab of Task Manager, but under the Processes tab (under the file-name of the EXE). This especially applies to programs being run in a hidden session by the Task Scheduler in Vista-and-later. In some versions of Windows you may need to select the option (if present) to 'Show processes from all users' or processes invoked by the Task Scheduler (etc) may be hidden.