Apple Power Macintosh 7500 Series - Manual (Page 165)

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 do this… …press this key combination
Start a “debugging” program used by software programmers* x -Power key
Start the computer from a CD-ROM disc C key (at startup)
Ignore SCSI ID 0 (zero) x -Option-Shift-Delete
Turn off system extensions Shift key (while starting up)
Rebuild the desktop Option- x (while starting up)
*If you do not have a debugging program installed, your screen displays a caret prompt (>). To return to the desktop,
type “G.”
155 Special Keys on Your Keyboard