Two weeks ago I upgraded to Mountain Lion from Snow Leopard (what was I thinking!), only to discover that it is not compatible with PPC apps. I returned the OS for a refund, and after visiting the local Apple Genius Bar, downgraded back to Snow Leopard. However, now I am unable to reinstall any of my apps, because Rosetta is gone. After another visit to the AGB today, I was advised to install Snow Leopard (from my original discs, since the install they did was of a newer version without Rosetta) on my G-Drive, then install all my apps there. I am not able to access my G-Drive at start-up by simply holding down the Option key. I remember having to toggle between drives when Classic was phased out, so I understand what I'll have to do now that I have opted out of using Mountain Lion. If someone here knows how to start-up both my MacBook Pro and my G-Drive so that I can do the install on the G-Drive, please let me know. In the meantime I'll keep researching. Thanks.