cleaning the laptop's memory

Memory failure can also result in the LCD does not work and make the LCD remains blank and does not display anything.
Just that if in this case on the desktop will trigger a beep sound from the motherboard, and the CPU will not working. remove the memory and clean the connectors with an eraser,both sides.
You may do this too with External VGA if you do not use the Internal VGA on your motherboard.

Well...You may laugh at the brush that I use .. I have to pinch it from the wall painter man ..  :-)