I have a Hansol 710a monitor. Just lately the display has become far too dark, even though the brightness and contrast are as high as I can set them using the control panel on the front of the monitor. Looking at calibration greyscale indicators there is definitely a problem. Can anyone please help me fix it. Thanks in anticipation.

Try reinstalling your video card drivers and monitor. See if the problem is corrected by using another monitor or try yours on another computer to see if the monitor is going.