Background slides wont advance..HELP!?!

Hi,
The American Space Museum has a webcast called Stay Curious that we do live every day at 4PM EST. We do space history, current space events, astronaut birthday's, and more. We usually have a couple dozen photos and graphics that we put up for each show behind the speaker(s). Everything worked awesome, and then we moved the computer to another location for a live shot at a launch. Now, when we start the show, at some point the slides will no longer advance, and there is a white stripe across the top of the screen... Does anyone know what this is, and how to fix it????

Thanks.
 
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