Two laptops are better than one

When running a meeting or any show that utilizes a computer, its a great idea to have two computers loaded with the exact same set of presentations and videos.  Because all computers have gremlins that strike at the most inopportune times it's an easy insurance to always have a back up.

Ideally, you can have two computer operators working with you so that as the computer that is plugged into the big screen advances, so does the back up.  If the master computer goes out for any reason (someone accidentally kicked the power cord loose two hours earlier...) you can quickly switch over to the back up, without taking time to load the presentation and get to the right slide.  It means a 3 second black out rather than 3 minute, which will absolutely destroy the momentum.