rebooting
hi, i've recently bought a new mac and i've been transferring across, i was in a bit of a mess getting mixed up, i had the two mac's on one account so i de-authorised my old mac, now i need to set it back up again for my niece to use but i can't get it going, the start up screen isn't showing the hard disk to select, and when i select reinstall it says the hard disk is locked. hope you can help. thanks ann
iMac, macOS High Sierra (10.13.1)