Black borders on left/right sides of Powerpoint Slide Shows ??

I have a customer running Office 2003 on his laptop at work. He can open power point presentations from 2003/2007, but when he tries to view them as a slide show the slides don't take up the whole page. There is an inch and a half thick black border on both the left and right sides of the screen. There are no toolbars, just the slide centered on the screen with black borders on the left and right sides. Any ideas? Is there a setting I need to change? He's tried a few different files with the same results. I tried opening these slides on a virtually identical laptop with Office 2003 on it and they are full screen during the slide show. ?? Any thoughts would be appreciated!! He is going out of town tomorrow and I need an answer today. Thank you in advance!