On the Stephen King.com website there is the possibility to get into Brady’s Basement. It has the same setup as in the book. With voice-commands or typed passwords you can get in to his computers. The passwords are the same as in the book; ‘control’, ‘chaos’ and ‘darkness’. It’s been more than 2 weeks since the release of Mr. Mercedes, so I don’t think it’s a spoiler to give you the passwords. (You ought to have read it already!).
Have a look and tell me what you’ve found…….. when in. If you read the book you know which computer is the important one.