I am working on a Dell D505 laptop. The display is dark when operating. When I put pressure on a small area near the power button the display will come to life with the normal backlight display. I have noticed when I put apply some light pressure on the left side of the power buton PCB (pushing it ever so slightly to the left) I will get the full normal display otherwise I get just a dark display. I have taken the laptop completely apart and cleaned underneath the motherboard. I have not noticed anything unusual that would be causing a short. What could be causing this problem? I appreciate any and all help with this problem.