Apple Power Macintosh 5400 series - Manual (Page 169)

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 to use while starting up
your computer:
To do the following at startup… …press this key combination
Start the computer from a CD-ROM disc C key
Ignore SCSI ID 0 (zero)
x
-Option-Shift-Delete
Turn off system extensions Shift key
Start the Extensions Manager Spacebar
Rebuild the desktop Option- x
157 Special Keys on Your Keyboard