Apple Power Macintosh 4400 - Manual (Page 183)

Special key combinations
If difficulties with your mouse or computer don’t allow you to use standard
methods of quitting a program or restarting your computer, you can try using
these special key combinations.
To do this... …press this key combination
Force a program to quit
x
-Option-Esc
Force the computer to restart
x
-Control-Power key
Here are other key combinations you may find useful while starting up your
computer:
To do this at startup… …press this key combination
Start the computer from a CD-ROM disc C key
Turn off system extensions Shift key
Start the Extensions Manager Space bar
Rebuild the desktop Option-
x
183 Special Keys on Your Keyboard