• Press X during startup : Force Mac OS X startup
• Press Option-Command-Shift-Delete during startup : Bypass primary startup volume and seek a different startup volume (such as a CD or external disk)
• Press C during startup : Start up from a CD that has a system folder
• Press N during startup : Attempt to start up from a compatible network server (NetBoot)
• Press R during startup : Force PowerBook screen reset
• Press T during startup Start up in FireWire Target Disk mode
• Press Shift during startup : start up in Safe Boot mode and temporarily disable login items and non-essential kernel extension files (Mac OS X 10.2 and later)
• Press Command-V during startup : Start up in Verbose mode.
• Press Command-S during startup : Start up in Single-User mode