I have an Lenovo IdeaPad Y560 and when I connect it to an external monitor using the VGA port, while the laptop is connected to AC power, some white lines of light are flashing over gray backgrounds. As I said, it has this problem only on the laptop is connected to AC power, on battery it is working normally. It seems that it may be some sort of a circuit problem with the VGA port. I've installed the latest graphic drivers. Do you know this problem ? Any possible fixes ?