The Western Digital hard drive inside of my MacBook has been loud lately, so I requested that they send me a new one. I received the new one, and I need to send them my old one within 30 days. Now, I'm faced with the dilemma of erasing the hard drive so my information won't be in the hands of someone else. So, what is the best way that I can erase the entire drive before sending it over to Western Digital? I'm not exactly sure how.