I have a 27UD58 with Windows 10 Pro, NVIDIA GeForce GTX 1060 3GB. All updates are installed. I have had it for a few years. Yesterday it started going black for about a second every 19-22 seconds. It also gitters or jerks at random times. How can I check if this is a monitor problem or some other system problem? - a diagnostic or settings tweek? I have extensive experience with computers on a non-professional level. I build my own computers and started working on computers in 1965.