I recently got a Surface Pro 3 for school, and out of the box it was amazing, with 9 hours of battery life. However, after a week or 2 of playing around with it, the battery life went from 9 hours to 3 hours. I am not sure if this is a problem with the computer or with windows 8, but I really need help fast, school is starting this week and 3 hours is just not enough! So far I have tried nearly everything with no success. I am going to reset my computer today to see if that helps!