Is there any way to prevent various "helpful" dialog boxes from appearing over Powerpoint? Yes I know that many of these troublesome notices (from windows defender, windows update, windows mail) can be tweaked in their respective utilities, but the REAL question is...

WHY OH WHY does powerpoint allow ANYTHING to appear on top of it when in slideshow mode??? The fact that these notifications are also from Microsoft just adds insult to injury. You would think that someone in Redmond would "get" that a slideshow is not to be pre-empted, ever.

Is there anything globally that can be done that would prevent ANYTHING from appearing on top of powerpoint?

There's nothing more exciting than running a meeting with hundreds of people or more in the audience, and getting a notification that you need to reboot after an update.