Computer display middle showing blue box

[boss123]

On my computer display showing blue box mentioned "Input Source" for every 10 seconds coming and going its to my computer work

 

[Kshipper]

It sounds like the monitor is losing signal very briefly, and just enough to flash on that blue box that is complaining about the input signal (like the computer has been unplugged from the monitor).

-Loose monitor cord at the monitor or the computer or bad cord?
-Perhaps there is a 2nd cord connected to the monitor that isn't connected to anything? I have never seen that be a problem but we are guessing here.
-Internal fault of the monitor...replace the monitor?