after replacing the screen on a dell inspiron 15r everything looked great for a while,picture was fine, colours were as they should of been,but after a few minutes the screen started to flicker and there appears to be what i can only describe as shadowing of anything that is on the screen.this only appears after logging into windows. i have plugged an external monitor into the laptop and that works fine. i have taken the new screen out and put back in all with the same result.i have changed the resolution etc, again this did not work......any help would be greatly appreciated