The movie is in the late 80's or early 90's. The girl tries to break-up with her boyfriend and goes crazy and won't let her and tries thought the whole movie to kill mom & dad and I think kills the family dog. I remember the home is a high-tech house with alarms, but she had given his the code when they were dating.

This movie was called Fear. Mark Whalberg and Reese Witherspoon. Here is a link to it... I Believe it is the one you are after... Fear (1996) (http://www.imdb.com/title/tt0116287/)

Thank you so much it was driving me crazy