Show Cue System

In our next production, we will be using some power point presentations. Now, I know that I should leave the sound cue system stand alone, but what I would like to do is set the slides to be called as part of a sound cue. I already have two display cards in it. So I guess the question is, if there is a way to echo a command out to another program, more specifically, the space bar in Power Point? I could just have the opperator switch between programs (but I think there are sound cues during the power point, and I can just see it now, instead of a slide changing, it's a car honking). Any ideas (yes we do have a seperate computer that we can use, but I would rather do it this way)?