I think the first thing to do is to tell which XBox, connections and more.
As I owned this XBox -> http://faq.teamxbox.com/detail/1/Xbox-Console-FirstGeneration/ it would go black and white if I had it on the wrong input through a VCR. Odd but did happen.
As there are newer XBoxes you might have to tell more.
Bob
It worked fine yesterday but today it's b&w. Anything I can do?

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