I have a projector mounted on the ceiling, the problem I am having is that the top right part of the image slants downward. So for example, the top of the image is an even 2 inches from the top of the screen until the last 2 feet. The bottom of the image is an even 4 inches from the bottom of the screen all the way across. So the only part that is wrong is the last 2 feet of the top of the image, it slants down about 2 inches. The fact that it's only the top right tells me that the projector is an even 90 degrees to the screen, so I am wondering why the last few feet slants downward, it's only a few inches but it's really noticeable. Any ideas?