Adult Children at home

My 19 yr old informed that since she is over 18, I cannot enter her room without her permission. Don't know why she felt it necessary to inform me, I don't just go into her room because she is 19. Anyway, the house is mine. I own it, it's paid for. She has no job nor does she seem motivated to get one. She quit college mid first semester. She will not pull her weight around here and picks a fight with me when the mood stikes her. When I tell her things like I don't want the boyfriend here today she tells me she has the right to have whomever she wants over at any time she wants. I ask her to be home at a reasonable time or call, she refuses. Is it legal for me to deny her a key to the house? She says she'd break a window if she were ever locked out. This is not the child I raised. I would be happy to let her live here as long as needed but I think because she is an adult, she should contribute something to the support of the household.I pay for everything she needs and those are the bare minimums since I am on a budget. She always wants better. I love her and don't want to turn her out in a hard world but I can't live with her like this. What are her rights concerning MY house. ( I'm not leaving it to her in my will.) She has nothing in her name except an overdrawn bank account. I want her to move out. I feel it's the only thing that will teach her about working and earning your material posessions as well as priviledges. I don't want to end up hating my own child and I won't end up raising grandchildren simply because of laziness.(She is not PG but I fear thats next) BTW, the boyfriend has only a part time job and he lives in his car which I have infromed him I would have towed if he continued to park it in front of my house. Don't know where he goes now but he returns here and somewhat treats my home as his. So, when and if it comes down to it, can I legally require my adult child to leave my home? Does she have to go because I tell her to or am I going to have to take action through a court?

Thank PS: Live in Washington State.