If you use PowerPoint often enough, you will face the problem of having a slide stuck during your presentation. What can you do in such a situation?
Computers are not perfect- they get infected with viruses, they get stuck, they get powered off- and so it will be no surprise if at some point, you have an unbudging, un-advancing slide on your screen. What i do not recommend is panicking or making a scene at the awful thing that is happening to you. Do not try and make it the most memorable part of your whole presentation as that is not what the audience should be taking away from it. It should be the ideas you gave to help them.
If the slides do not advance, just black out the computer and talk to people. Act as if you couldn’t care less whether or not the slides work. You will be able to do that only when you are prepared. You should be able to give the presentation without the slides which is why you should have a sheet of paper with the outline of your presentation on it for your reference. The presentation is not the slides, but you.
So the solution is to be ready to give the presentation without the slides. Just keep speaking without talking about the aberration. You can restart your computer and try to pull up your slides again but do so while talking about your ideas instead of stopping and bringing the attention of the audience to the computer.