Command-S Boot into Single User Mode Command-V Boot using "Verbose" mode (shows all kernel and startup console messages) X Reset startup disk selection and boot into Mac OS X Server Shift Boot into "Safe Boot" mode, which runs Disk First Aid. A reboot will be required afterward. Option Boot into Open Firmware to select a boot device Command-Option-Shift-Delete Bypass internal harddrive on boot T Boot into Firewire target disk mode C Boot from the internal optical drive N Start from the Network (NetBoot) Command-Option-P-R Reset Parameter RAM (PRAM) and non-volatile RAM (NVRAM) (mouse button) Eject (internal) removable media ALSO: if you use open firmware password... you'll need this: Startup Manager -accessed by pressing the Option key during startup Enter commands after starting up in Open Firmware -press Command-Option-O-F key combination during startup. http://docs.info.apple.com/article.html?artnum=106482 How to troubleshoot a computer with Open Firmware Password enabled If you cannot access the Open Firmware Password application and need to troubleshoot your computer by: Resetting the PRAM Starting up in Single-user mode Starting up in Verbose mode Starting from CD-ROM Then follow these steps: Start up into Open Firmware by pressing and holding the Command-Option-O-F key combination during startup. At the Open Firmware prompt, type: reset-nvram Press Return. When prompted for your password, enter it and press the Return key. It responds OK. At the Open Firmware prompt, type: reset-all Press Return. The computer restarts and you are now be able to reset the PRAM and startup in Single-user mode, Verbose mode, or from CD-ROM.