Apple PowerBook G3 - Manual (Page 9)

m You see a picture of a disk with a blinking question mark on the screen.
This icon usually means that the computer can’t find system software on
the hard disk or any disks attached to the computer. You may need to
reinstall system software. See “Reinstalling System Software” in Chapter 6.
Turning the computer off
Always use one of the following methods to shut down the computer. If you
don’t, you risk losing any work you haven’t previously saved on a disk. You
also risk losing any open documents.
Turning the computer off with the Power key
To turn the computer off, press the Power key. Detailed instructions follow.
1 If the computer is in sleep, press the Power key (or any key on the keyboard except
Caps Lock) to wake it.
For information on the sleep feature of your Macintosh PowerBook, see
“Putting the Computer to Sleep,” next.
2 Press and hold the Power key for about two seconds.
The following dialog box appears on the screen:
3 Press the Return key on the keyboard (or click the Shut Down button in the dialog box).
9 Getting Started