I'd suggest going through the "skills tested" and checking out those that you already know. If you are familiar with Windows 7, you will find that you are already knowledgeable on many of the points that are listed there. Then take the few ones where you
are not certain of your knowledge, and look them up in your book. This should make a much smaller subset than the 840 pages.
Don't worry about "scenario" questions. If you have actually installed Windows 7 and you have performed on your machine the kind of tasks that are being tested in the exam, you should have no trouble at all answering the questions.