It can happen that your new LCD monitor is having dead or stuck pixels which can be rather unfortunate depending on the location of the pixels and the laws of the country you bought the monitor in. Some dead pixels on a newly bought monitor may not be enough to return it.
It can also happen that dead or stuck pixels appear after using the LCD monitor for a while. It’s a good idea to test the LCD monitor before or immediately after purchase with a software that can reveal stuck or dead pixels. The best case scenario would be obviously a test before buying the monitor to be sure that it does not contain dead pixels.
The tiny application Is My LCD OK [via Shell Extension City] provides several test color schemes that reveal if pixels on the monitor are not working properly. It can be run from any location on the hard drive. The first start uses a German interface, press E to switch to the English interface.