Change Your Boot Disk in OS X

To change the disk your computer boots from is easy. You can do this right from System Preferences in Mac OS X Leopard. You might want to do this if you want to boot from an external disk or network drive. Follow these steps:
Step One
Select System Preferences from the Apple menu at the top left hand corner of the screen.

Step Two
Select the Startup Disk icon from the System Preferences window.



Step Three
The Startup Disk Preference Window will popup.

Step Four
Click the lock at the bottom left of the window.

Step Five
A window will popup asking you to enter your administrator username and password. Enter your username and password then click the Ok button.

Step Six
Notice the lock at the bottom left hand corner of the window becomes unlocked.

Step Seven
Select the disk you would like to use as your start up disk from the list across the top of the window.

Step Eight
Click the Restart button to restart the computer and set your new Startup Disk.