Question mark when MacBook turn on?

Either your HD is trashed, or corrupt. You can boot from your install CD/DVD and run Tools->Disk Utility->Disk First Aid Tab->Repair Disk. (Do not do an install).

If you don't have/can't find your install disk you could try booting into single user mode and running a utility from the command line.

' Startup in single user mode ( hold down command-s after the boot boing ) you'll see white text on a black screen. When it stops loading/scrolling type /sbin/fsck'' press return.

1. /sbin/fsck <- run this until until it is clean''' (no longer says "System modified) it will say volume appears okay.
2. # type reboot press return

If the above fails boot in target disk (hold down the T key until you see the firewire symbol {looks like a stylized Y}

• You can now use a dual USB or Firewire cable to connect your laptop to another computer, and backup your data.
• Reformat and reinstall the OS - if that fails your HD is cooked.

Good Luck.

N.