How do I fix?

Download samsung kies here is the link

http://www.samsung.com/uk/support/usefulsoftware/KIES/

install kies you might need it. But for now here is what you need to try. Power of your phone. Then your gunner need to hold the home key on bottom front of phone and the up key on left side of phone and the power button it shud boot up giving u a menu once booted. On this menu use your side keys on left of the phone to scroll down or up. Scroll down to (wipe cache partition) PRESS The POWER BUTTON. THEN USING ARROW KEYS GO TO (wipe data factory reset) AND PRESS THE POWER BUTTON. THEN GO UP TO (reboot system now) Press POWER BUTTON TO ENTER. Once this has done its thing your phone will reboot and start to go through the phone setup. At the end of the setup is were it will ask for you to setup samsung account at this stage you can sign in, or skip this, or create new account. Try this let me no how you get on.