Hello, I have a Toshiba laptop Model: Satellite M35X-S149 P/N: PSA72U-00T00U. The problem I am having is that the LCD screen has turned white as though only the backlight is functioning. If I plug a monitor into the external VGA port I can get a display on the external monitor. Has the LCD gone bad or is there something else I can check before shelling out 700+ dollars? I am computer literate and a Avionics Tech so getting into the guts of the computer won't be an issue. Thanks in-advance.