Hi baz and welcome to VBAX

I assume you're talking about doing this in slideshow view, which is tricky because the active slideshow will always be on top.
If you want a second slideshow in view, you'll have to manipulate the size of the slideshows in kiosk view. This in turn might then require a blanking slideshow in the background to hide the desktop/windows behind.

Do you need an actual slideshow in the popup? If you're just displying a slide, then exporting the slide you want to view and putting it on a modeless form might be easier...

Let me know, I'm sure we can come up with something