The solution is simple when u have a small black dot on the desktop!
If a black, or even different colored dot on the desktop appears, you should clean the screen (LCD, TFT, Plasma) with a cleaning cloth.
If it does not help, they test the monitor with the Freeware IsMyLcdOK.
If the pixel error persists and it is within the warranty period, you may get a replacement device from the manufacturer, when has been informed of the presence of dead pixels.
... Software IsMyLcdOK to find paralyzed or dead pixels!
FAQ 4: Updated on: March 25th 2014 12:46