THis scenario assumes that you have a preloaded Mac OS X
installed in an alternate drive, or using another Mac Machine
with the Mac OS X. Let's called this alternate drive
'Mac AD.'
Booting Your Mac machine from a Mac AD
From a external harddrive, attach it to the Mac machine
via a FireWire cable. Upon boot-up, hold-down the the
'Option Key.' You will see the all bootable drive appear on
the desktop as shown below. With the mouse pointer,
select the the desire drive to boot-up from.
After boot-up, you may wish to carry on working with your Mac or perform a Mac OS recovery by using Mac OS X CD/DVD. To boot-up from the Recovery CD/DVD installer, you may follow the same steps laid above, or you maywish to start the computer by holding down the 'C' key on the keyboard.
Booting up from another Mac(Good Mac) to mount your Mac (problem Mac)
Attach both Mac together via a FireWire cable. Ensure that the Good Mac is alreday powered-up and you are able to view the desktop. From your Mac, hold down the 'T' (for Target) till you see a floating FireWire logo on your Mac as illustrated below.
From the Good Mac, your harddisk will be mounted on the desktop.
You may back-up your file, work on them or you may target the mounted harddisk to restore the Mac OS X.
