AMD Radeon HD 6550D display adapter does not display video for all video types. Only a black screen with audio was displayed. The utility that looks for updated drivers said that the best driver was installed. Only uninstalling the driver and allowing Windows 10 (64 bit) to use its own 'Microsoft Basic Display Adapter' corrected the problem. This was only after a lot of painful attempts to solve the problem. Anyone who wants more details can contact me via email at email@example.com.