I can think of several times when technology did not cooperate for a presentation. My MO is that if I do not immediately know what is wrong and can fix it within a few seconds, I scrap the technology altogether. If there is a glitch, the audience’s attention is immediately strained. If one fiddles with the technology for a time, my feelings are that they will lose the audience altogether. Therefore, if I have to ditch the technology, I share a laugh with the audience (we have all been there), and use the power of my voice and storytelling.
It is also important to note that preparation and setup is of vital importance. If one commits the time to properly set up and test equipment, the likelihood of a technological glitch is minimized.