For various reasons your computer may occasionally freeze or be non-responsive. To close a program that is "not responding"; try pressing the Ctrl, Alt, and Delete keys all at the same time.

The Ctrl+Atl+Delete key combination:

By executing this key combination, the Task Manager window will be displayed. Click on the Task Manager button and choose the Applications tab. The window will list all the active programs. The stalled program will have "not responding' listed after it. Click on this program and then click on the End Task button. Be patient -- sometimes it will take a while for the computer to properly end the program.

If End Task is successful the program will close and you will lose any unsaved changes. (Save your work OFTEN.) Once you have closed the stalled application, save any other unsaved work, close all open programs and then restart your computer.
If End Task is unsuccessful, the computer or program will still be stalled. Press the Ctrl+Alt+Delete keys again and choose Shutdown from the Task manager.

If the above procedure does not work, you will need to manually turn off your computer. If your computer has a reset button push it. If it does not, hold down the power button for 5-10 seconds to completely turn it off. Wait 30 seconds before turning it back on.