This was an English movie I saw on HBO or Showtime or something in possibly the mid-90s. It may have been sci-fi, or horror but it was definitely a B-movie.
It started with this film (maybe VHS or reel) that someone found and started watching. The movie within the movie was a 1940’s-style futurist sci-fi where a man in the woman are showing what life would be like in the 1990s, complete with a giant electric toothbrush apparatus. There was something about this movie that caused people to die when they watched it for some reason, but I’m actually not even 100% on that part.
I’m having a heck of time finding anything close to this through google.