The Western Digital drive in our iMac 2008 broke down. I had to replace it with the backup one I made with Superduper!. It took me 2 hours to do so. I found the help I needed on the iFixit website. I borrowed 2 sucking caps from my garage to remove the glass in front. It almost fall out of it. Just magnets keep it there. I also ordered a new (Toshiba now) drive to act as new backup. Paul Moortgat