My asus lcd monitor recently shows blue rectangle in the middle of the screen, its see through, it doesnt hide the desktop, but its annoyingly there

If the picture disappears from the screen and the
1 (power) indicator is green
1
Turn off the 1 (power) switch and disconnect the
video signal cables from the monitor.
2
Turn the monitor on by pressing the 1 (power)
switch.
If all four color bars appear (white, red, green, blue), the monitor
is working properly. Reconnect the video signal cables and check
the condition of your computer(s).
If the color bars do not appear, there is a potential monitor failure.
Inform your authorized Sony dealer of the monitor's condition.
Be sure to note the model name and serial number of your
monitor. Also note the make and model of your computer and
graphics board.

try a new cable.

Sounds like your main board is going out. It's cheaper to buy another monitor then fixing it unless you have a warranty.

Unplug the power from the monitor, wait for 10 seconds, plug back in. Worked on my ASUS Monitor

If the laptop boots up all the way and you don't see an image on the lcd screen or on the external monitor then the video card inside the computer is bad.

Shine a flashlight on the dark screen to see if you barely see the icons on the desktop. If so, then the LCD Inverter is bad.

Plug in an external monitor and see if the display shows up on it. It can be any kind of monitor even the old big fat crt monitors as long as it has a vga cable to connect to your computer's vga port. If the video shows on the external monitor that proves your video card is ok, ,but your lcd screen is bad. The video will show on most systems when you reboot without you having to do anything. Some systems will require you to hit the FN (Function key) + F1 thru F12. Hold down the FN key then hit the correct key for displaying on the monitor (F1 thru F12). The correct key will normally have CRT/LCD on it or it will have the icon of a display.

If you see no icons by shinning a flash light and the external monitor works, then your screen is bad. If you see no icons by shinning the flash light and nothing shows on the external monitor, then most likely your video card is bad.

Takeout the powercord at the back of the monitor and wait 5m.
Put it back.
This fixed it for me.

its an issue with the monitor vga cable the monitor cable is unplugges or there is and issue with the graphic card if u have or u can try to replace the monitor .

Please check whether the monitor is set to the correct settings. If you feel its incorrect, most LCD/TFT monitors come with an auto set up button which will restore the display to one that usually works. In case it still doesnt work, you might need to connect your pc to a different monitor and check the display settings. You could also try to download the drivers for this monitor and then re-connect the monitor and see if it works.

buy a new one

the refresh rate of your computers graphics card is set either too high, or too low. right click on the desktop, select properties, go to the settings tab, and click advanced. then go to the Monito tab, and play around with the different refresh rates, until the picture will show up. This is usually, around 60 Hz or less.