This is an older post, but for anyone having issues and has not found a solution. I called Samsung support and this is what they had me do.
Unplug everything (yes, everything) from the TV, even the network. Go to settings and locate Reset SmartHub. Reset Smarthub. Let it finish the reset. Then below that is another Reset. Select that and let TV reboot. when it comes back up it should start the setup as if it were a new TV. Go through it step by step. Make sure to agree to all of the terms and policy when you get to it. Connect the cable box if you have one. Connect the network when it asks for it. Keep stepping through the step up until you get to the end. When you finish, you should be able to operate the functions as you did before.
