Apple PowerBook (3400 series) - Manual (Page 27)

Trouble? If a problem with the computer prevents you from using the Power
key or choosing Restart—for example, if the computer “freezes” so that the
pointer does not respond to the trackpad—you can restart the computer by
pressing the Command (x), Control, and Power keys simultaneously.
If the computer doesn’t restart, press the reset button (marked with an I) on
the back of the computer. (If the computer is on but “frozen,” pressing the
reset button will turn off the computer. You will then need to press the Power
key to turn it on.) Use this method only if you cannot choose Shut Down or
Restart from the dialog box that appears when you press the Power key, or if
you cannot choose either command from the Special menu.
27 Getting Started