Mac OS X can boot differently than to your default startup disk with the use of modifier keys. When you power a system on, using these keystrokes will send commands to the system to perform the following: C – Boot to optical media. D (with restore disk in optical slot) – Boot to hardware test mode. Command-Option-O-F – Boot to OpenFirmware (if you have open firmware). Command-Option-P-R – Reset Parameter RAM. Command-Option-P-R (until you hear two tones) – Reset non-volatile RAM. Command-Option-N-V – Reset non-volatile RAM (similar to above according to hardware). Command-Option-Shift Delete – Bypass the default startup volume and look for another blessed volume. Command-Option-T-V – Boot that…