buy a new screen/faceplate....nextime dont purchace kenwood products...sry dude sh*t happens ,been there.. by alpine or atleast research reviews next time u purchase anything.hope u get it workin.
then the screen dies like that it's usually one of two things; the voltage regulator that handles the voltage to the LCD display/CLF bulb, or the actual backlighting bulbs, which are the most common to go, since an LCD is backlit by way of a fluorescent bulb and diffuser panel behind the LCD panel. In any event the bulbs for a display that small would probably have to come from kenwood themselves, and it would be expensive to replace. You may be better off replacing the entire display if this is just a display itself. If this is the display in a flip-out head unit, send it in to a kenwood repair auth'ed center.