Ok, this is all I remember about the movie. It was made around the early to mid 1980's and also took place around that time too in the movie. It was a suspenseful thriller about a girl that lived in this house back in the 1800's and under this house was a treasure. A 100 years or so later some people came to the house. The way they got under this house was a secret door at the fireplace. Through the movie they went through the history of this house, saying that the girl fell down the stairs that were behind the fireplace and died. And that her soul couldn't rest until she was found, or something like that. I haven't seen this movie for about 20 years so I'm sorry if the plot is vague.

Sounds like Mystery Mansion (1983) (http://www.imdb.com/title/tt0091587/)

Yes, I think I know this movie as well but not the title. At the end did the kids who were in it find the skeleton of the girl in a deep hole in the fire place?