This unnamed woman is the the mother of Max Miller and wife of Jim Miller and was killed by being pinned to the ceiling by Azazel after making a deal with him.
At some unknown point for unknown reasons this unnamed woman made a deal with Azazel and in the deal Azazel would be able to enter her house. At an unknown point this woman broke her deal with Azazel and Azazel ended up killing her by pinning her to the ceiling.
In the episode "Nightmare" Max mentions to Sam Winchester how his mother was pinned to ceiling with fire bursting out of her chest. Sam telling Max how his mother died was exactly how his mother, Mary was killed. A frantic Sam tells Max that they must be connected in some way.