Black screen on toshiba satellite

Hello,
My Toshiba satellite a105 s1014 has a black screen. i baught a new battery, a second memory card, and a new backlight (inverter) and it's STILL black. When i turn it on the power light is green, i hear it loading but nothing ever appears on screen. I've tried hitting the F8 key when starting and that doesn't work either. It's also black when connecting an external monitor so there's no way of getting to the control panel. Can someone PLEASE help me ???