I know this might sound stupid but do you have a TV card fitted in your LapTop?
Some TVs can not cope with the graphic data from a computer and will only display it in Black and White, check with the LapTops Manufacturers web site, they often have helprooms like this one on them, and have online professional help, or they might suggest a third party device which will help you with your problem.
It may be something to do with the way you have connected the laptop tothe TV. I do not think that connecting SVHS to the yellow video in on the TV works correctly. It should be SVHS out to SVHS in OR VIDEO OUT to VIDEO IN. Whenever I mistakenly set my video input to SVHS when its just composite video I get all sorts of strange happenings - including a B & W picture.