Most LCD TV screens can be replaced or repaired by a professional. LCD screens are made of liquid crystal in between two pieces of glass with a plastic covering over the top. Cracks can occur in the glass and cause the liquid crystal to flow out and ruin the display.
A crack in an LCD screen may not be seen or felt because the plastic covering over the top usually does not break. Cracks in the glass can leave black spots and streaks when the display is turned on. Light spots are often caused by a sharp or hard object gouging the screen, and broken glass may only be visible in the case of a major break.