Unable to power on, flashing blue charger

And my girlfriend had this tablet for a long time and said one day it just stopped working and she hasn’t messed with it since. It’s been several years and I don’t know if it’s able to be fixed or not. The only button accessible is a power button so all online tutorials telling me to push the reset button are inadequate. Has anyone else found any solutions for this? Do I need to replace the battery? What could be causing the flashing blue light inside the charger hole?