On occasion, Microsoft presents Webcasts on interesting subjects.
Unfortunately they are usually offered at inconvenient times for people with real jobs.
Fortunately they are offered in a form that you can download or watch "on-demand".
Here's one on how to find and fix problems with PowerPoint presentations.
"This Support WebCast will define troubleshooting issues in Microsoft PowerPoint and provide an overview of when and how to use available resources such as product Help and Microsoft Knowledge Base articles. We will also discuss how to determine where a problem is occurring and how to troubleshoot specific issues such as printing, opening a file, installation, movies, and starting the program."