In what sense? To disable mouse click in the presentation (so that users can
only advance to slides through hyperlinks/buttons)? Or to disable all
interactions including the hyperlinks & buttons?

To disable mouse click, simply click Slide Show > Set up show.
Under show type, select browsed at a kiosk.

If you want to disable all interactions, after setting up the "browsed at a
kiosk", add a 'lock' button (you will need to create one yourself) on the
slide. Then, insert a rectangle that covers the entire slide. Set the
transparency to 99% so that it becomes invisible. You will then need to
create a trigger so that when user clicks on the lock button, everything is
lock up.

For the latter part, I won't go into detail as it will become a little wordy.
But if that is what you want and you need further help, feel free to post
back.