My new Panasonic Viera tv is showing black and white please help!?

I just bought a new Panasonic Viera 50 inch tv and it's showing black and white when I put it on the component input. So if I try to plug my Wii into it it only views in black and white. I have called Best buy and they replaced the tv but it is still doing the same thing. I have also tried useing different devices to see if the cord for the Wii is broke but it does the same thing to everything i plug into it. Please use simple answere with small words because I'm not a very good with technoligy(I know very sad seeing that I am 20) but i just want to try to fix this without spending anymore money then I have to. Thanks.