Dual screen slideshow help!

[aspen135]

Hi,
Basically i have my pc connected to a projector (hdmi), i need to run an uninterrupted slideshow through the projector (cant be closed/minimised/windowed) for 10+ hours, essentially cycling through 100 slides. I need to be able to drop in different slides as the show cycles over the long period, which im hoping i will be able to do on my pc.

I heard there is a simple way to do it by maximising a windowed preview in some slideshow software, but when i change the slides on my pc the slideshow on the projector does not update automatically, it requires that i restart the preview before it will update the changes.

So im looking for some software that will allow me to edit a slideshow on a pc while the actual show on another display will update the changes automatically without interruption.
sorry if its hard to understand what im trying to do, im not very technically minded. Hope someone can help!

Thanks