Hi, I am interested in setting up Time Machine on my MBP. I think I'm having a problem or it's me being stupid. I believe when I was originally setting up my MBP, I chose not to select Time Machine as the back up disk and to use an external one. Since then I have changed my mind and want to get Time Machine up and running. How do I select Time Machine as the back up disk? I can't seem to figure it out. I open Time Machine through System Preferences and then when I turn Time Machine on or hit Select disk, the notice on the 2nd ss appears. No option to select Time Machine as a back up disk. HELP the noob please. Thanks.