Apple MacBook Pro (Late 2007, 2.4/2.2 GHz) - Manual (Page 50)

50 Chapter 4 Problem, Meet Solution
If your MacBook Pro freezes during startup, or you see a flashing question mark,
or the display is dark and the sleep indicator light is glowing steadily (not in sleep)
The flashing question mark usually means that the computer can’t find the system
software on the hard disk or any disks attached to the computer.
 Wait a few seconds. If the computer doesn’t soon start up, shut it down by pressing
and holding the power (®) button for about 8 to 10 seconds. Disconnect all external
peripherals and try restarting by pressing the power (®) button while holding down
the Option key. When your computer starts up, click the hard disk icon, and then click
the right arrow. After the computer starts up, open System Preferences and click
Startup Disk. Select a local Mac OS X System folder.
 If that doesn’t work, try using Disk Utility to repair the disk:
 Insert the Mac OS X Install Disc 1 into your computer.
 Restart your computer and hold down the C key as it starts up.
 Choose Installer from the menu bar, and then choose Open Disk Utility. When Disk
Utility opens, follow the instructions in the First Aid pane to see if Disk Utility can
repair the disk.
If using Disk Utility doesn’t help, you might need to reinstall your computer’s system
software. See “Reinstalling the Software That Came with Your MacBook Pro” on
page 58.