Hi @daisyface ,
Try a power reset and see if this resolves the problem.
Turn off the TV
Turn off the TV wall power outlet and remove the TV power cord
Press and hold the TV's Power ON button for 30 seconds and then release the button.
Plug in the TV power cord back into the wall outlet and turn on the outlet.
Switch on the TV and see if it now works OK.
What is the model number of the TV?
Were there any storms or blackouts just before the problem occurred with your TV?