this is my pastors macbook. First of all it will not fully start. I get the apple logo start screen with a progress Bart that goes roughly 1/4 through, then stalls, progress bar disappears, then a few seconds later the computer shuts down. The AHT reports no trouble found. Disk checker reports no troubles found as well. Attempts to restore the. OS reports that the boot disk is locked. How do I unlock that drive?