SOME slides disappear on laptop screen but show on TV

[dlsherman]

I have many many powerpoint presentations set up for our music at church. We recently added a flat screen tv for the congregation to be able to see the words to the songs. Now on the laptop that we look at random slides disappear from the laptop screen but show perfect on the TV. I have gone through the same song multiple times and the 'missing' slide or slides seems to change randomly. One time all of them will show except slide 4 then the next time slide 4 shows but 6 and 7 dont. It makes no sense.