I have a Sony Vaio which only has a VGA output and bought one of the small converter boxes that converts the VGA to HDMI. Have plugged the VGA in to the Laptop and box and the HDMI cable into the box and the Panasonic TV. I have set up on the Laptop the secondary monitor with the resolution required for my TV. I have switched the TV to HDMI channel 1 but I am getting nothing on the TV just a blank screen. Any advice would be appreciated.