techwood hdtv looks like its on acid. any ideas??????

i have a fairly new 32"widescreen techwood Lcd hdtv.
its got a great picture but it keeps going crazy. blues seem to turn to bright greens and purply dots/distortions, i can still just about see the images on the tv but the colours are twisted. and then it'll go back to normal for a few hours (sometimes only minitues).
any ideas?? cost to repair?

much appreciated