I know I'm one year late but I hope I can still answer this.Just like Protestant Christians who don't acknowledge the existence of ghosts of the deceased returning to possess and cause harm but believe that demons do, Muslims also don't acknowledge the existence of the ghosts but acknowledge the existence of Djinn/Genies. Even though in some Muslim countries they have many ghosts from local(non-Arabic)folklore, the Ustaz(Muslim wise teachers?)that are invited to give talks on TV frequently remind Muslims that these are just folklore and that ghosts do not exist. An alternate explanation that they sometimes give is these "ghosts" from folklore do exist but are actually Djinn and that it is only through the mouths of the people that they ended up being called ghosts.
With that out of the way, one of the differences between Demons and Djinn is that Demons are the fallen angels but in Islam Djinn are not. They are creatures of fire that were created by Allah before Adam was created and that Satan was one such creature. I don't know about this part but supposedly Satan became the leader of all the Djinn that sided with him. Djinn are known to be creatures that have varied forms and can possess humans or be sent by witch doctors and shamans to a victim for a fee to cause havoc in their lives. I read from their(modern day books) that Djinn can have different religions and can even be atheists.