Holding down the Control, Alt, and Delete keys simultaneously the computer will perform some action, depending upon the operating system being used. Check the list of actions by OS.
What is Ctrl+Alt+Delete?
Holding down the Control, Alt, and Delete keys simultaneously. This action produces the following results (depending upon the operating system being used):
MS-DOS:
Restarts the computer.
16-bit Microsoft Windows, Windows 95, and Windows 98:
Shows running tasks and allows you to terminate a task. A second Ctrl+Alt+Delete will restart the computer.