How to help students when they don't want it.

What to do about a student who doesn't want to be helped.
A student who is usually full of life came into class and kept herself apart. She took a computer and logged in. When I went to check in with her she avoided my gaze and started crying, but really wanted to not be noticed. I gave her a note to deliver to a teacher who was not teaching this period, but she just wants to be left alone. I have no idea what has upset her, but this class have a lot of stuff going on, with parents that cannot be contacted, or parents that are in jail, or long histories with CYFS. I really think she needs to talk to someone, but I feel at a loss of what to do when she doesn't want help.