It seems that Windows had crashed on her laptop. She re-booted and tried again and again. Windows eventually went through some sort of recovery process and then booted up successfully. Once Windows finished booting, a new discovery was made: the PowerPoint presentation for her talk was not to be found on the laptop. After a frantic search, she found that the entire presentation was gone. By this time, the room was standing-room-only with more than 100 genealogists politely waiting for her to begin. It was now three minutes past the scheduled start of her presentation.
Now for the worst part: there was no backup copy available that she could restore quickly, at least, not in time for this presentation.
She did find an older presentation still on the laptop about a related topic so she displayed those slides and started her presentation nearly ten minutes late. She talked about the differences between the slides being displayed versus the ones that were no longer available. It seemed to work well and I doubt if many people in the audience knew the difference. However, the presenter's hard work in preparing those slides was wasted: nobody saw them. Her only backup copy was back home on another computer.
I have written often about the needs to make multiple backups of all computer files onto multiple forms of media and then to save them in multiple places. Let's add one more: if you are going to give a presentation and plan to use PowerPoint slides or something similar, take along a jump drive. Copy your presentation slides and notes to the jump drive in advance and then place that jump drive into your pocket or purse. Make sure you take that jump drive with you to the presentation room.
If you, too, hit a last-minute crisis, you can always grab the jump drive and plug it into your own or possibly a borrowed Windows or Macintosh laptop and then proceed.
An ounce of prevention is worth at least a pound of cure.