A dead pixel is a defective pixel that remains
unlit.Dead pixels are usually best seen against a white
background.
A stuck pixel will usually be most visible
against a black background, where it will appear red, green, blue,
cyan, magenta, or yellow, although stuck red, green, or blue pixels
are most common. Each pixel on an LCD monitor is composed of three
subpixels, one red, one green, and one blue,
which produce the visible color of the pixel by their relative
brightness. A stuck pixel results from a manufacturing defect,
which leaves one or more of these sub-pixels permanently turned on
or off.
Stuck pixels are not guaranteed to be correctable, and can
remain faulty for the life of the monitor. A stuck pixel might be
fixed with JScreenFix, a Java-based
application that flashes numerous colors with a very rapid
intensity.
--from wikipedia..a wonderful source of info..