my girlfriend wants to sell her ibook and get a macbook. she was looking into selling it on ebay or craigslist, but i warned her that if someone who knows their way around computers may be able to access her personal data that may still remain within the computer. am i wrong in my thoughts? i just don't want her information exposed to some stranger via her ibook sale. thoughts? ps. is there anything she can do to the ibook to avoid any dangers like this?