About this situation you may choose the "region cover", in middle of screen has a black block, like pic below:

There are 2 ways:

1. Close "region cover":Main menu--System --Display --region cover(If you have selected this option,please cancel and you will not see the black box on the screen)

2. Resume to default setting:Main Menu--Advanced--Restore(System will require a reboot,but don't worry after reboot the screen will be normal)