I am not a parent so I do not have experience in this area. But, the first thing I would do is take the computer out of her room and put it in a more active part of the house. That option would get her out of her room. Plus, she is young and apt to make stupid mistakes. You should be monitoring her computer use and know who she is talking to and what she is doing.

If I remember correctly 13 is a very difficult age for a girl. I remember not being sure who I was anymore or how I should act. My friends were all going through their own changes and I found I could not relate to them anymore. Your daughter is probably in the throws of being a teen ager. Maybe she just need to know you still love her and support her and are intersted in what is happening to her. She needs your help to get through this stage. It is not an easy journey.