@vagelis48076 there is no fix for this. What you are looking at is a failed LCD. You would have to try to find a new display for that. Remove the back cover and you will see a label that is stuck to the back of the LCD display. There should be a model number on that. Do a search with that number. Most of the time replacement LCD's cost more than a new TV, so see if you can maybe get a used one or even find a TV that uses the same LCD and has issues other than a bad LCD. You could then harvest the LCD from that.