Predator Laptop screen doesn't turn on when not connected to a second monitor
For the past month, I've been having a very strange problem with my laptop. Normally I keep it connected to a second monitor, and disconnect it when I need to bring it somewhere (school). However, it stopped working whenever it wasn't connected to that monitor. Whenever I would boot it, the built-in keyboard would stop working and the screen would be on (backlit) but nothing would display. Plugging it back into the monitor would fix this.
Today, however, not even plugging it into the monitor would fix it. I tried everything, including reinstalling Windows, and that finally worked, however, now only the monitor screen would turn on, not the screen of the laptop itself. I eventually fixed this by changing the display settings: the laptop screen had set itself to 300.18hz refresh rate, and changing it to 300.19hz made it turn on again. Regardless, it still doesn't turn on at all when not connected to the second monitor. How do I fix this? I just need it to work without using a second monitor all the time.