Is it an LCD monitor ?
When an LCD screen has turned completely white, there are three normal causes: the screen is defective, the video cable is not connected correctly, or the graphics card on the motherboard of the computer is faulty. You will need to troubleshoot these possibilities to determine which problem you have. If you are not experienced in working on computer equipment, you should not attempt to disassemble your LCD screen because you could easily damage it. Seek professional assistance unless you have experience working on computer hardware.
Disconnect the white LCD screen from the computer by unscrewing the blue monitor cable. Connect the working LCD screen to your computer by attaching its blue monitor cable to the same slot. If your computer display does not show on the functioning LCD screen, try rebooting your computer. If it still does not display, the problem is with your computer's graphic card on the motherboard. Seek professional repair assistance. If your computer display shows normally on the working LCD screen, proceed to Step 2. Unplug the LCD monitor with the white screen. Disassemble the rear panel of the monitor with the small screwdriver. Carefully separate the screws into piles so that you can keep track of how to reassemble the monitor. Locate the internal video cable, a gray cable with a plug on the end that connects to the main components of the screen. See Below for the References section for photos of the video cable for assistance. http://www.laptoprepair101.com/laptop/2008/04/13/laptop-lcd-screen-turned-white/
Unplug the cable, checking for any debris or blockage. Reconnect the cable firmly. Reassemble the LCD screen. Plug it in and connect it to your computer. If the screen is still white, you have a defective LCD screen. You will need to replace it or take it to a professional repair service for assistance. Hope this helps.