Hi, I've just used Disc Warrior on my startup disc (booting from DW disc). I've ejected the DW disc but am now unable to boot from the internal drive. I've tried pressing Option at startup to select startup disc but all I get is a picture of a padlock with a space underneath to enter a command and an arrow next to this on the right. It appears to me that System Prefs are locked and I need a command to unlock. Can you help?