Sorry to hear you're finding broken links. If you can let me know where you're coming across these broken links, I'll look into fixing them.
We do have a slideshare account where you can find many of our presentations: https://www.slideshare.net/numenta
As @subutai mentioned, if you have specific slides you're looking for, let us know that, too. If they're not publicly available, I can track them down for you.