and when the menubar appears at the top of the screen, choose utility and reset all the passwords.
You may have to start the installation before the menubar appears but don't worry about that, you will see the menubar a long time before the installer will actually do anything.
Reset the passwords and reboot
HELP!! Imac refuses to log me in!!?
So when I startup my imac there is a grey loading bar. Then when it shows the user screen with the accounts. I tried logging in to my account and the password was correct and everything, it turns white for a few seconds, but it goes right back to the user screen and that happens to the other 4 accounts. PLEASE HELP!!!!! all my important notes i took are on that imac and i dont want to have to lose any data and all the photos on there.