ACER LCD Monitor X233. Cable not connected message from day 1, but dual display was initially working. VGA cable used. Recently I connectde the laptop to a PLasma TV via same VGA Cable and used it to view photos. When I connected the Laptop back to the ACER Monitor it did not display anyhting except the the cable not connected message. The monitor is picked up staright away when connected to another laptop. Any ideas would be appreciated.