I'm trying to restore my in-law's 13" Macbook Pro (A1278) that was "accidentally" upgraded from Snow Leopard to Yosemite. I'll spare the details, but they are utterly lost in Yosemite (e.g. Appleworks no longer works, and they have tried in vain to grasp Numbers and Pages to no avail.) Fortunately they have a back-up of their files, never used iPhoto in Yosemite, and this should be a straightforward rebuild. I have the Snow Leopard retail Family Pack Box Set (MC210Z/A) that included iLife and iWork. When I try to install SL on the MBP, however, the DVD begins to boot, but each time I get a Kernel Panic before it gets to the end. My next step is to try installing with the MBP in target mode. Then, Plan C is to clone a SL drive I built on an external drive to the MPB and hope to high heaven that works. If anyone has insights, I welcome them.