New admin and password
I was going to sell my MacBook Air and deleted all the accounts made on it. Turn around, someone went and made an account on it without me knowing. Now there is a padlock with a required password that shows up, I believe this password is for the person that made the account. There is another problem when not pressing anything when booting up a blinking file with a question mark shows up. Well I checked everything online and nothing helped. I ordered a thumb drive and a SuperDrive to try and fix this problem. I didn't get a boot up CD either on purchase, just the computer and power cords with the manual of how to work the computer. Can someone PLEASE help me on this and how I can fix it without having to send it out. P.S. I have called apple and they said it could be a possible hardware or software problem, this is the reason for me buying software and the SuperDrive as I have found someone with a CD. Thank you very much in advance.
MacBook Air, iOS 8.3