I purchased a dell 2400mp projector for a conference room at work recently. Today I finally finished installing everything mounting on the ceiling, screen etc. Everything works fine thus far, but the one problem I am having is making the image straight. I cannot seem to get the bottom left corner to be align. I've tried playing around with the horizontal and vertical keystone but doesn't seem to help. Anyone have experience with this problem or could it be a manufacture defect?

Are the other 3 corners aligned? If so, keystone won't help.
Is the projector itself horizontal or on an angle?