This is one of the serious problem
that arises because if you set your monitor
with a high resolution with high frequency, then the monitor
doesn't display anything as it's frequency is out of the rang or limit of the monitor's
actual resolution capacity.
will have a limit of max frequency that is said to be the Refresh rate (for each and every resolution setting the display is refreshed.)
When high resolution is set with high frequency that is not supported by the monitor
, it then display a message like "frequency out of range". If you press ESC key within the few seconds of this setting, it will revert back to its initial resolution.
But if you continued with the setting of same High resolution with High frequency, the monitor
is not going to display anything because its frequency is out of the range.
Most of old monitors
like CRT's etc doesn't support 1024×768 at a refresh rate greater than 60Hz.