If you are struggling with an HP Laptop not starting up Black Screen, hard reset the laptop as it is one of the best ways to eradicate any conflicting settings that could be causing the problem. To go about it, first of all, turn off the laptop and remove the battery and any other hardware components connected to it. Next, press and then hold the power button for about a minute and release it. Put the battery back and plug in the charger, but make sure to not reconnect any other hardware components. Boot the laptop and check if the issue is fixed. If the problem has been solved, you can connect the hardware devices one by one until you find the one causing the problem. Disabling fast startup is another way to fix the issues. For that, open the control panel and then click on "Power Options''. Then, click on "Choose What Power buttons do" and choose "Change Settings that are currently unavailable" Lastly, uncheck "Turn on fast startup" and then click "Save Changes" to fix the HP Laptop not Starting up Black Screen.