Ctrl-Alt-Del - technical definition

The key combination in Windows that enables a user to end an application that is not responding. All three keys must be pressed at the same time, which brings up a list of open applications that can be forcefully ended. It also enables the user to reboot the computer.

First used in DOS PCs to reboot the computer, the keystrokes were chosen by IBM in 1981 to ensure that users did not reboot accidentally. The Del key is at the opposite end of the keyboard from the Ctrl and Alt keys. See Command-Option-Escape.