Most of the advice out there concerning this topic is infuriatingly infantile, like "make sure advance on click is enabled", etc.
If you've tried the rest and your PPT still randomly stops on a slide and refuses to advance MANUALLY no matter how hard you try, and you're not in Kiosk mode or whatever, it is possible that your PC is just running out of puff and can't manage the PPT any more.
This obviously SHOULD NOT happen, especially with modern PCs, but it seems it might if:
• You have "Do not compress images" checked in Options / Advanced; and/or
• Your PPT output resolution in Slide Show / Monitors is set to a high resolution (either manually or by default).
It seems this combination causes Powerpoint to try to render your uncompressed images at a high resolution, which obviously strains the CPU / video card.
I find it incredible this is even a thing, but compressing images and setting the output resolution to a more manageable level stopped my PPTs from refusing to advance slides at semi-random points. So it is obviously a thing.
I have older machines that have no issues with this - only my "modern" Windows 10 laptop is affected. It's also the only one that operates at an insanely high resolution (3k x 2k), meaning it's most susceptible to this issue - especially with the relatively wimpy Intel onboard graphics. An ancient Win7 laptop runs the same PPTs flawlessly.