Yeah my dad just got a new HDTV and when i try to connect the Wii the output on the screen is just black and white i've tried using all the different ports (whatever there called) and it just stays black and white :\
Blue and green are HD spots. To plug in standard you must have red white and yellow. Red whit are left and right speaker audio. Yellow, blue and green are video. Blue green being HD only. I think there is another HD video color too but I forget.
if it's black and while it could be the Hz (Hertz) on the tv do not support HD from what i've been reading, if you haven't changed the wii settings to 480i in the wii menu, i suggest you doing that, if that doesn't work i also suggest going back to SD component cable (Red, while and yellow).
Maybe one of the "white" is a faded yellow? I have never heard of two white in one. Try putting one "white" in a yellow switch them if it wont work. It is at least worth a shot! If you get nothing try to set up something else that uses the same cables to make sure the television isn't the issue. Even though it's new it can be messed up!
those are component cables and need to match those to the tv. you should have a red white yellow and he is probably using the green or blue plugged into the yellow on the tv which is why it's black and white.