i have brought new dvd screen for my car of newvision company,the shop man showed me by insterting song video,after reaching hme i hve installed from shop near to my hme whn it was installed in my car nw im insterting the dvd cd the voice is coming but the screen is showing "no video while drivng" is there any settings i hve to do,or any one knows what problem is tht.?