I would recommend getting the PowerPoint file from the customer and editing in post, adding the slides.
The problem recording from the laptop, you need to know what kind of output the laptop has (15 pin VGA, DVI, HDMI) you would also need to have pass through device to go to the projector. Lots of variables to deal with or to go wrong. You also need to know what resolution the laptop will be set to.
If you have the PowerPoint File you can output the presentation as a movie and set the output to the resolution you will need matching the format you are recording the event in.
If the presentation being recorded is going to be live streamed then you will need to do your homework well before the event and I would recommend testing before the event to make sure everything works.
Everclear Video Productions
Sony Cameras, FCPX