Well, that depends entirely on your laptop's model.
Tell me, what do you mean by not working?
Do the fans/hard drive make noise? Any leds lit/flashing? Any sound through the speakers?
Here is the most likely solution to your problem:
Cause: you extended the wires going from the LCD inverter to LCD backlight.
Why not? -the signal coming from the LCD inverter gets weaker when the wires get long.
Solution: instead of extending the INVERTER<>LCD cable, try extending LAPTOP<>INVERTER cables, this way it will work no matter how long you extend it. The key is to keep the INVERTER<>LCD cables (two of them) as short as possible. Just slap the inverter board to the back of your LCD and forget it
With that said, I am pretty sure that your laptop works great, only you don't see anything on the screen since your backlight doesn't work. As soon as you do what I said above you will see everything perfectly