Picture problems. Hi my name is theo and im having a problem with my tv. It just went into lock

Question

Hi my name is theo and im having a problem with my tv. It just went into lock down mode. None of the buttons on the remote work and all the buttons on the tv dont work either. It just has a blue screen and a red little lock in the upper left hand corner. I dont know what to do so if you could help me i would really like that. Thank you for your time.