You need to find out why you had grade F in every class. Follow up with the teachers and see how they can help you. Some of the reasons why you may get a grade F include; cheating in a test, lack of being responsible and missing classes. Be positive and develop new study habits.
You need to study harder. And judging from your other question you also need to take school more seriously. Unless your life goal is to work at McDonalds for the rest of your life you need to focus on the material and study harder.
If you aren't studying or trying start right now! If you feel you study and do your best but still fail, talk to a teacher to see if you can get study or organizational tips or possibly start the process to find out if you may have a learning problem.