Gateway laptop screen is black

Hello, I have a gateway laptop that won't show anything but a black screen. When I press the start button, you can hear the fans running but nothing shows up on the screen. I have tried taking out the battery and holding the start button for 30 seconds hundreds of times, but it doesn't work. Also, I don't think it's the screen that doesn't work, it's something with the laptop itself. If anyone has any advice, I'd really appreciate it!