blue and red screen

hi ya room i hope someone can help me, i no its not the right place to put this but just after a bit of help .. got a 21 inch lcd tv in my sons bedroom , he does use it alot for xbox live & and xbox games , anyway today all of a sudden the picture has gone blue and green almost like a negative picture , ive done a bit of reading on different sites but no real info on this problem just wondering if any one you nice people ( well you allways sort my replay lite box out for me )would have any ideas on this , or no of any sites that might beable to help me with this problem ..

many thanks