If, in this position, the first thing you do is open up PowerPoint, then you should probably first spend some time developing your presentation skills. Delivering an inspirational or captivating presentation requires a lot of preparation and work, and you may not even need PowerPoint at all!
Many people feel terrified when asked to make their first public talk, but these initial fears can be reduced by good preparation which will also lay the groundwork for making an effective presentation.
Find more at: http://www.skillsyouneed.com/presentation-skills.html#ixzz3hNWnaQ5J