My laptop screen is blank when it's turned on???

If you have tried pressing the brighten button at the top of keyboard, then you may need a new inverter board or new backlight. A new backlight is a bi.ch to replace because it's soldered onto the screen and you have to take the screen apart to access it. That's why tech stores would rather just sell you a new screen. A new inverter board is relatively easy to replace depending on your skills and patience. If the above doesn't remedy your problem, then you have an issue with the graphics chip, which means replacing the entire mother board or removing the bad graphics chip and replacing it.