A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
If this will be a show controlled by a user (as opposed to one that runs automatically), a mouseover might actually do.
Add a rectangle to cover the entire slide, make it transparent and assign it a mousover action to run your EXE, it should do what you're after. The user's sure to move the mouse a bit and when they do, your EXE gets fired off.
Of course, PPT, ever mindful of your safety, will then toss up a warning message. The world as we know it, after all, might end if you were to allow an EXE of your own choosing to run on your own PC without MS warning you. Somehow the fact that they interrupt your presentation makes it all safe. Don't ask me why.
To get round this, if you can use VBA, you could do a little macro like this and assign it as the slide-covering rectangle's Run Macro on Mouseover action:
Sub NoStupidWarningsForMeThanks()
Call Shell("NOTEPAD.EXE", vbNormalFocus)
End Sub
Substitute the full path to your program in place of "NOTEPAD.EXE", obviously.
And don't tell MS or they'll break that too. ;-)
If it's an autorun show, different story.