Apple PowerBook (2400c) - Manual (Page 81)

The sleep indicator light in the PowerBook’s latch glows a steady green.
m You must reset the computer using the reset button. Connect the external
power adapter (if it is not already connected) and press the reset button
(marked with the icon I) on the back panel.
When the reset procedure is used the computer will thoroughly test the
RAM, so it may take a few moments (testing takes about 1 second per
megabyte of RAM) before the screen lights. Be patient if you have added
expansion RAM.
The computer makes an unusual sound at startup, or you see a “sad Macintosh” icon.
m If you hear the sound of breaking glass when you turn on the computer or
you see a “sad Macintosh” icon, start up the computer with the Disk Tools
floppy disk that came with your computer. If the computer does not start
up, or if the hard disk icon does not appear, the hard disk may need repair.
Contact an Apple-authorized service provider or call the Apple Assistance
Center. If the hard disk icon does appear, see Chapter 7 for information
about reinstalling the system software.
m There may be a problem with the information stored in the area called
parameter RAM (PRAM). Reset the PRAM (also called “zapping
the PRAM”).
Resetting the PRAM erases the contents of your RAM disk, if you have
one. Resetting the PRAM also restores the default settings in most control
panels. After you reset the PRAM, be sure to check any custom settings
you made for the desktop pattern, memory, network, AppleTalk, trackpad,
power conservation, and so forth. Resetting the PRAM also resets the
power manager.
81 Tips and Troubleshooting