Monitor problem. theres a space at the top of the monitor of the stv2763 thats acting like a

Question

theres a space at the top of the monitor of the stv2763 thats acting like a mirror of the image on the screen. whats going up on the screen is in this small space going down. its not blocking the that part of the screen but both images are showing. there are horizontal lines in this part of the screen. its a mirror effect.