Ok we aren't too high tech but hubby is looking. It's hooked right from the roku box to the back of the TV with a cable that has 3 connections-one yellow, one red & one white. When it was working OK the imput said video 1 but after the TV had to be reset it suddenly changed to component 1, and we had no color.
Sounds like you are not hooked up correctly. The Red and White connections are for the audio and the Yellow is for the video. If the Yellow is connected to one of the component connections, then you would probably get a black and white picture. You want to make sure the yellow cable is plugged into the yellow connection on the TV. That will most likely say Video 1 on the back of the TV and the red and white will be next to it most likely.