The number one cause for students not being engaged in the classroom or not paying attention, etc. is the instructor and the way the situation is being handled. You must first evaluate that you have done everything you can do to engage and motivate them. Once you have done that, you can then determine a course of action to get the student on track. External pressures often affect the students' performance as well. Determining your part and whether or not external pressures are having an effect, you can then begin working on specific strategies to get the student on track.