Turn Pictures or PowerPoint into Video
Windows makes it pretty straightforward, if not completely easy, to turn your PowerPoint presentations into movies using Windows Movie Maker. This program comes standard on Windows machines or can be downloaded from Microsoft for free.
It allows you to import pictures, video, and audio together and drag and drop them in whatever order you choose - and weave them seamlessly together into a single video.
In order to convert your PowerPoint slides into pictures, one need only do a screen print (cntl-print screen) and paste into Paint (another standard Windows program) or other picture editor, crop to a standard size (crop all slides to the same dimensions for video continuity), and save each screenshot with a descriptive name to help you sort out which order and content each slide picture file contains (makes it easier to match slide order with audio files later).