Hello. I'm doing a full erase and clean install of my OSX from the boot disc however I cant remember what drive to click erase on when I'm in the Disk Utilitiy menu. Do I do a full erase on the actual physical hard drive titled '250 GB Toshiba Media' or the volume icon just below it titled 'my mac hdd'-? I've looked up a few youtube videos but some do one, others do the other. Which do I erase to do a clean install? Thanks.