Hi I just got a new computer and am selling my upgraded mac mini for parts, including the 320GB hard drive. It does have personal stuff (photos, videos, quicken, probably passwords or something). I want to sell it on ebay. How do I format it so no one can get the info off of it? I'm a little paranoid about hackers and whatnot. What kind of weirdo would buy a used 320 laptop hard drive? Thanks.