オリジナル投稿者： Jason Heiken ,
Your hard drive is most likely dead if it shows up as Disk 1. If your MacBook Pro came with 10.7 or later, you can use [http://support.apple.com/kb/HT4718|Internet Recovery] to get the OS back on it after installing a new hard drive. If it came with 10.6 or earlier, you'll need to install off the restore disks. However, you say you can boot off your external drive. Is that just a regular install of OS X, or does it a backup/clone of your internal drive that has failed? If it's a clone of your old drive, you can install the new drive than clone the external back to the internal. If it's a backup, or it contains a Time Machine backup, you can restore from that once you install the new hard drive. I have not provided instructions for every method I mentioned, but if you need help, let me know and I'll do what I can to walk you through the process.