This video provides ten handy keyboard shortcuts for Windows. I think most readers who use Windows will find one or more tips in here that they find useful. In the video are shortcuts including reopening a closed tab in your web browser, pasting text without formatting, quickly snapping windows to the side, instantly screenshot to a file and more.
For Mac users, the makers of the video also have a similar one for Macs on their YouTube channel, HouseholdHacker. Via Laughing Squid
When you open a Powerpoint file, and you want to start the presentation, people usually go to View and then Start Presentation or some such.
Just press F5. This will start the presentation right up.
(This is the standard key for "refreshing" a screen or view. It will also work to re-load a web page on your browser)