are the following steps the right ones to reset a macbook to it's factory settings? 1. Turn off MacBook 2. Hold the power button + option key till the screen comes on and then let go of the power button but keep holding on to the option key 3. When the screen comes on choose "Recovery HD" 4. Choose "disk utility" 5. Click the macintosh hd tab on the left 6. go to the erase tab and erase the macintosh hd 8. reinstall osx to macintosh hd is this correct?!