LCD dead pixel means pixel that are not able to display the correct color. It may look like a tiny black spot or any other color that does not correspond to what the actual image should look like.
Dead pixels are not an uncommon thing and expect to be having some degree of dead pixels. But if the amount is large the screen is considered to be defective. So it is wise to check that your monitor has dead pixels, especially if it is purchased recently.
DeadPixeBuddy is a tiny and portable program. Just download and run the app. Run through the color on the left and check for pixels that do not match the selected color.
IsMyLcdOK is also a tiny and portable program and effective solution to easily check for dead, paralyzed and stuck pixels on LCD monitors. This application tests 8 different colors, horizontal and vertical lines on your LCD. Just click on numbers shown on the screen to test your LCD.