You certainly don't want to depend on the Internet being available, which is why I suggested using only links to files that are on the memory stick itself. This does mean learning HTML, but you only need a very small subset of its features to get more communicative effectiveness than PowerPoint.

Browsers are reliable, stable, predictable in what they need from an OS or other support software, and multiplatform. PDF is pretty good as well, but not as portable as file-based browser technology if you want to include sound files and videos.