I have a 2007 MacBook Pro (non-unibody) that recently started freezing / lagging. Further investigation revealed 300+ errors on the hard disk so I decided to swap it out. I bought a Hitachi 500GB 7200RPM drive and did the upgrade my self. Now, this is my first time doing a hard disk upgrade, so I was exceptionally careful and I'm pretty sure that I got all the connections secure, no loose contacts etc. However, when I tried to use the install disk image on my external HDD to format + install the new disk, it does not turn up in the left hand side column where it should. Am I doing something wrong? - Thanks, I'd really appreciate your help.