Asus X55U. When unplugged, the monitor goes dark. Please advise the solution

create new acount

check your video card settings and output selections. You may want to check and update drivers for your video card to ensure they are current.

Power down your computer and press all of the function keys (F1, F2, etc) on your keyboard. Also, press delete and tab as well. I'm wondering if a key is sticking that is the key to get into the BIOS.

go to www.asus.com and download the driver

You need to enter the bios to set up the correct boot order to install the new OS from a medium.

You can download the device drivers from ASUS WEB site. Select your model motherboard/computer/laptop, and make sure you select drivers that matches your Windows operating system. Please click on this link to their WEB support site : -
http://support.asus.com/download/download.aspx?SLanguage=en-us

Does that monitor work on another computer?..if yes,then try uninstalling your display adapter,loacated in devices manager,reboot your system and windows will reload the drivers.Make sure you have the monitor plugged in when you do this.You may also want to try setting your windows color resolution to 800x600(medium),as the monitor may not handle higher resolution...good luck..please let me know if that works:)

Return the monitor to ASUS for repair or replacement !!

Device Manager/MonitorDisplay/Reinstall/Update

It sounds like a LCD backlight problem. Bring it to an authorized repair shop.