When trying to figure out what to include on your slides for your final defense, cutting a dissertation down to around 25 slides can, at first, seem nearly impossible. However, I assure you that it can be done, and that you can do it!
An important thing to remember at this point is that you are no longer trying to convince anyone of why your study should be done. You have already done that. You are, however, aiming to discuss what can be done with the results of your study. If you defended your proposal, you can use much of what you had there to build the final defense presentation. When it comes to reiterating what you had in your first defense, be sure not to use any more than one slide for each section, if possible. Cut the literature review and method descriptions down to a couple of bulleted slides. Any extra information that you are hoping to touch on can go in the notes section of the power point. The notes section can be one of your biggest assets during the defense. You can use it to record any supporting statistics or even small details that you may be afraid you will forget in the moment. Also, you can add as much in the notes as needed without the pressure of needing to cover all of them if you start to run short on time.
For your results section, be as concise as possible. Only report what you found and stick to your main research questions; anything beyond that should go in the discussion slides. For the last part, think back to the highlights from your Chapter 5 (the implications, recommendations, and conclusions); cover each of these sections with (at most) one slide and a few bullet points. Finally, close with a thank you and questions slide.
We work with graduate students every day and know what it takes to get your research approved.