Hey i need some help!

I saw this movie around 10 years ago on TV, its an english/american movie. It was in color.

So a family moves into a big estate. Mother, Father, daughter and 2 little brothers. The daughter finds out there is a ghost in the house, her parents dont believe her. Her little brothers try to trick the ghost by fooling around with some knight armor i believe. To get her parents to believe her, she plays out some scene on the stairs/balcony. Anyway, the girl finds out the ghost isnt a bad guy and she tries to help him pass over or something. I believe she finds his tomb by using a stone/gem above a fireplace and it opens a pathway of some sorts.

Ring a bell? PLEASE HELP!