|Tell us the make and model of your brand name system, or if you have a generic desktop system, the make and model of the mboard. |
The message is being generated by the monitor itself.
It probably displays the same message when it has not been plugged into the computer's video port, when the monitor is powered on, after a short time.
You could try connecting the monitor to a working computer - you'll probably find there's nothing wrong with the monitor.
A friend of mine has an el-cheapo Acer LCD monitor model - it works fine, but it has a very short time period it waits before displaying a message similar to yours, and you briefly see that message while booting the computer before Windows has loaded, every time. That's of no concern.