A post on August 3rd at The PowerPoint Blog described Oh the many ways to advance a slide.
Their seven were:
1] Right Arrow
2] Page Down
3] Space Bar
4] Enter Key
5] Down Arrow
6] Mouse Click
7] Remote Advancer (wireless controller)
I usually stick with a remote. But, It’s also useful to know both how to get to the next slide and the previous slide just using the keyboard. There are five ways shown above, including the N and P keys.
I don’t recommend using a left mouse click to advance, and a right click to go back because you cannot depend on these options working. If you’re presenting on someone else’s computer, they might have been reset.
For more keyboard shortcuts, see the Microsoft and Dummies web sites.
Users of Keynote on Apple Mac computers will find that these same combinations work, except that Enter and Backspace are replaced by the analagous Return and Delete keys.