Each modern MacBook comes with the original Mac OS as part of the computer’s package. If your MacBook is not performing as expected -- running slow or not loading applications properly -- you can restore your MacBook to the factory settings to fix it. In some cases, this will repair whatever is not working correctly with your computer. However, when restoring the computer to its factory settings you are removing all your files and personal data.
Insert your MacBook restore DVD 1 into your computer and restart the machine. Hold down “C” as the computer boots so it will boot from the disc.
Select your language and click “Continue.”
Click “Options” at the Select a Destination window.
Choose “Erase and Install.” Click “Continue.”
Choose “Basic Install.” Click “Install.” Once the install is complete, your MacBook will be restored to its factory settings.
You may have to insert the other restore DVDs as your MacBook asks for them. Restoring a MacBook to factory settings can take an hour or more.
Back up all important files on your MacBook to an external drive or DVD before you restore the factory settings.