The Viewfinder screen is black
when I turn on my camera the viewfinder will not show anything.
Does anything show on the screen when you press the DISP button?
Try taking a picture (I realize that you cannot “see” what you’re taking) and then download it to a computer.
If the picture is OK then there is a problem with the camera’s LCD screen.
If the picture is just a black image, then there’s a problem with the camera’s image sensor or the motherboard