Hi @thisismurica
Try connecting an external monitor (TV?) to the laptop's HDMI port and check if you get the laptop's display showing on it. Don't forget to press the Fn + F9 keys (both together) to toggle the laptop's display output between the laptop screen only, the external monitor screen only or both on together.
***If you do see a display on the external monitor,*** try shining a flashlight at an angle close to the laptop's screen and check if you can see any images at all. Don't forget to switch the display output back to the laptop screen.
They will be ''very faint'' if they are there so trying this in a darkened room may help to see them.
''If you can see images on the laptop screen'' then there's a backlight problem with the screen. This could be a faulty backlight power supply on the motherboard (blown fuse or power mosfet?) or a faulty video cable.
Further testing of the motherboard, using the schematics for the board, would be required to find out what's wrong. I couldn't find a free download online for the schematics but I did find this [link|https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-laptops-tablets-and-mobile-devices/schematic-requests-only/105313-request-ga503qs-schematics-boardview|website] that appears to have them but you have to join to be able to download them.
''If you can't see any images on the laptop screen,'' as you have already tried replacing the screen, then it could be a faulty video cable.
***If you don't see a display on the external monitor,*** the there's a problem on the motherboard and further testing would be required to find out what's wrong.
Hopefully you turned off the laptop and disconnected the battery from the motherboard ''before'' unplugging and plugging in the screen. Plugging the video cable back in again if the laptop was on or even if it were off and the battery wasn't disconnected, could've damaged the video circuit i.e. blown a fuse on the motherboard if there is one or perhaps even a power mosfet that supplies the backlight power if there isn't a fuse.