Some keys and keyboard combinations on your MacBook were born for Startup magic — either to get your Apple laptop booted up, help troubleshoot computer problems, or perform other technical tricks within Mountain Lion.

Key Effect on Your Mac
C Boots from the CD or DVD that’s loaded in your optical drive (if you have one)
Media Eject Ejects the CD or DVD in your optical drive (if you have one)
Option Displays a system boot menu allowing you to choose the operating system and/or volume
Shift Runs your MacBook in Safe Mode, preventing your Login Items from running; runs a directory check
T Starts your laptop in FireWire or Thunderbolt Target Disk mode
Command+V Boots from the Mavericks Recovery HD
Command+V Show OS X Console messages
Command+S Starts your MacBook in Single User Mode
Command+Option+P+R Resets Parameter RAM (PRAM)