my apple logo doesn't shows up instead of it there is folder with a question mark on it?

Click here and follow the instructions. If the computer was running Mac OS X 10.6.8 or earlier and you reach the third set of steps, insert a Mac OS X install disk.

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Likely a hard drive failure. You could boot from an external hard drive with an OS installed on it, or boot from original disks (if you have some/originally supplied). You could also create a new startup disk if you have another mac computer to do so.