I've been very happily using Flashback to create software demonstration clips for some years now. I record the screen, export the recording as Flash, and then embed the resultant Flash file within a PowerPoint slide.
This works perfectly for me as it allows me to combine text and graphic slides alongside 1-3 minute clips of the software that I'm demonstrating. I'm running PowerPoint 2016 under Windows 10 on a Dell XPS13.
But I just now tried to run my PowerPoint file for the first time in a few weeks and the Flash content was blocked. I had to manually click on a dialogue box to release the Flash content each time I called up a slide with a Flash object.
This is issue is documented on the link below but frankly this is a bit beyond me. Is there any help on how to fix this?
Support for Flash is being withdrawn pretty much across the board with most major browsers completely ending support for it within 2 years and some applications already starting to block it. There's not really much we can do about this, I'm afraid.
As far as I am aware, PowerPoint accepts MP4, WMV, AVI and MOV so I'd suggest that you try one of those instead. MP4 or WMV would probably be your best bet.
Of course, none of these formats support interactive elements like Flash can so if you include any of these in your recordings, there isn't really an alternative to trying to follow the guide you already found. If you do try to follow it, be very careful because modifying the wrong values in the registry can cause serious problems. If possible, I'd recommend just using a different format instead.