When buying a display, it is best to use a dedicated application to make a full quality test (such as whether it has dead pixels), so as to avoid identifying problems during later use. At this point, IsMyLcdOK can be a good and effective solution. Its file size is only less than 50 KB, runs directly without installation, also does not need other runtime environment. In other words, you can use a USB flash drive to take it with you when choosing and testing a display.

When facing a older LCD monitor, you might find one or several obtrusive dead pixels, then you can try to use UDPixel to repair!