Replacing laptop LCD panel

Solution 1:

Are you certain that the new panel works at all? Basically there are two possibilities here - the panel is not correctly attached in the sense that something isn't seated properly, or something's wrong with it. Third possibility is that you forgot to reconnect something - as long as the inverter card and cable are reinstalled that should be pretty much it, though. Fourth possibility is that you damaged something but that's unlikely.

If the screen is unlit but you can make out an image with strong illumination your backlight isn't cutting on and probably the inverter isn't reinstalled properly. (There also may be a bad backlight on the panel but that's unlikely.)