Apple Power Macintosh 8600 - Manual (Page 229)

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
Bypass the internal hard disk and start the x -Option-Shift-Delete
computer from a System Folder on another drive
Turn off system extensions Shift key
Start the Extensions Manager Space bar
229 Special Keys on Your Keyboard