I have a Toshiba Satellite P205D-S7438 17" laptop. When I turn it on, I get horizontal white lines from the top of the screen to about 1/4 of the way down and the remaining 3/4 of the screen is black and blank. I read that the symptoms may be either a bad LCD Inverter or the backlight. I replaced the inverter as many said it was the easiest to do for troubleshooting... It didn't fix the problem. Now could it be that the backlight bulb is bad or is there something else "internal" that I haven't seen or read about that could be the problem??? I connected the laptop to an "external" monitor and it works. I can view the desktop and do whatever I want. I welcome all thoughts and opinions! Thank you!!!
Your issue actually sounds like a bad inverter, a backlight would either leave the screen uniformly dark or light in areas, you would not see horizontal lights like this. Unelss you maybe have an LED backlight which are pretty rare now.
After the inverter change, does it all look exactly the same? You may have damaged the LCD screen itself. Was this dropped, gotten wet, etc...?
If you checked all the cables and installed the inverter properly, next step is replacing the LCD panel.