Chosen Solution
So my installed a new screen for my laptop. It works great at first but my second reboot I encountered this problem. It only dims when the laptop is prompting for for user pin code. The screen works when I entered BIOS config mode. It just so happens that it dims when logging into windows. I already ruled out a blown backlight fuse because I can access the BIOS. Not sure if this is a hardware or software problem.
Edit 26/12/2021: Just found out that it works when I entered safe mode. This could maybe have to do something with the LCD Lid Sensor.
Hi, What is the model number of the laptop? If it works OK in safe mode then there is a driver problem as only generic Windows drivers are loaded in safe mode and not specific hardware drivers. (video drivers?) Try connecting an external monitor to the laptop and check if the problem occurs on it as well. If the external monitor stays on alter the lid settings and check if it is the switch
