One of the major problems encountered with LCD monitors is the “dead pixels”: all of a sudden we start to see white or black dots that remain visible regardless of what we are displaying.
Fortunately this kind problem is covered by any major monitor warranty and if we start to notice those dead pixels in time before the warranty is over, we can ask for a RMA. But there is one catch before we can send the monitor to the manufacturer: are we sure that those apparently dead pixels are indeed hardware-ly dead and it is not just a bug in the graphics card drivers or in the operating system itself?