Yes, as said... unregistered???
The best way is to do this combination keys, but it could be another problem, that the Hard disk is broken and don't recognize it.
When you start your mac the HD sounds? Try to open mac case and put the hand over the HD and you feel how it works, if do clack, clak, clak... like the arm of the HD jump... its over
you need another HD...
Otherwise, if HD starts and no jump, try the key combination... if not... you need the software.