I have an imac OS X 10.9.5 and forgot the password to the main user. I've tried all the tricks of resetting the password but none work. When I restart after pressing the appropriate buttons a screen pops up with a lock on it. I think I might have activated the firevault. Is there any way to break in?? P.s. I can access a secondary user but can't actually do anything... because I don't have the acces key.