You probably have ever had a laptop which can be powered on, but shown blank screen. This could be a problem with the video of the laptop if the problem is not on the LCD. Whether it's LCD problem or not, you can try connecting it to external LCD. If you can see something on external LCD, then the problem is on the laptop LCD. If you can't see anything on the external LCD, then this could be the problem of your laptop video chipset.
If you go searching on the internet for solution, like youtube, you probably will find suggestion like BGA rework or reflow the motherboard with an oven. In here tin foil is used to protect other parts of the mainboard, so that the process is focused on the video chipset only. I'm not an expert on laptop. But, this post is created as my tips on repairing laptops only. Just for my own laptop repairing tip only. Hope that the following video will help those who are looking for solution on such laptop video repair.