Blackscreen issue with windows 10

I encounterd a blackscreen upgrading my HP pavilion 17 to windows 10 a while ago. i suspect, but cannot be certain, that the issue was not there to begin with, because I had read reviews about the problem and therefore kind of anticipated it. If it would have occurred right away after the update I would have noticed.
Anyway, as i had the black screen I put the computer into power saving mode, once returning from it the computer worked normally. Somewhere along the bootup trouble I checked the screen with a flashlight, and there was an image, only the lights were off. Onwards, with advice from HP support I found out that booting the computer without the charger worked ok, albeit with a dim screen. Some musing on the problem and I found out that if you find your mouse cursor with a flashlight and turn your screen brightness from 100 to 0%, the screen returns to full brightness. from there on, 25, 50 etc the screen grows gradually dimmer until in 100% it turns completely black. Without the charger plugged in the same happens, but less pronounced, even with 100% brightness the screen doesn't turn completely black.
So, the problem is that screen brightness settings are, for some reason, inverted.

That seems like a display driver problem and since you were apparently able to use the computer before the upgrade I doubt that the problem is your hardware itself. Does your laptop by chance have an ambient light sensor? If it does it could be the driver (system chip set driver probably) for that, that is the problem. I found this article when performing a search about this issue. You could see if it provides you with some incite on the problem as a start.

How to fix Windows 10 brightness control not working issue

Alternately there is also this article about adaptive brightness in case your system has an ambient light sensor.

How to Disable Adaptive Brightness on Windows 10 for Maximum Screen Brightness Windows Tips

Good Luck and Welcome to Windows 10 forum :)

This seems to be a common problem, the same thing happened to a friend of mine after updating his video card. It happened to me when installing Windows 10 fresh into my PC. I had to wait for Windows to download a suitable display driver. My friend's PC video eventually came up, after rebooting it a few times.