Please try these two things before turning in your Chromebook for repair.
Make sure your Chromebook is charged and your power cord is plugged in all the way to your charger.
Try to restart your Chromebook by holding down the power button and the refresh button (above the #4) at the same time for 10 seconds. After that try to power back on and see if that helps.
If these two things do not work, you may turn in your Chromebook to Mrs. Mange in the library. She will send it for repairs and will let you know the estimated repair time as well as estimated costs. You are responsible for all repairs and damages to the Chromebook throughout the school year.