If anything goes wrong with your slides or the equipment, don’t panic, keep cool. It happens to everyone at one time or another. The problem can probably very easily be fixed, and there will be several people ready to offer assistance. Best of all, the audience will be completely sympathetic to you.
What should you do instead?
Don’t make a fuss about the equipment and draw even more negative attention to yourself. Remember that the audience is not expecting perfection, they’re not expecting the rapid pace of a TV show, but they DO want you to keep going and show you are in control.
Remain calm and proceed as best you can. There are no marks at stake and nobody will sack you! Take your time, tell the audience something they will find interesting, show enthusiasm for your topic, and just keep going. I have a planned recovery technique if this happen to me. I have a funny little story that I tell that distracts the audience from the staging man who is frantically trying to get it all back up and running. Maybe you should do the same?
Try where possible to have a back-up just in case you have to ditch the slides all together. After all, you’re not there to show a slide show. You’re there to talk to the humans! If you’re passionate about your content and flexible with your visuals (this means you can whip out a whiteboard marker, or grab some flip chart pens and draw it instead) you’ll wow the crowd without the slides.