Unable to change screen brightness in Windows 10 or with brightness buttons

[natemack29]

I have an HP Envy Touchsmart 15t-j100, running the latest updated WIndows 10 64-bit (1903). It has the Core i7 4700MQ processor. Just recently I noticed that I am no longer able to adjust the screen brightness at all, either in the display settings or with the fn brightness buttons on the keyboard (f2 and f3). I have tried every possible troubleshooting method I could look up for similar HP issues reported. I've ensured all display and monitor drivers are the latest and up to date, tried uninstalling and reinstalling the drivers in Device Manager with no effect, ran a full system scan with cmd, and even reset the device, fully reinstalling Windows 10. I also attempted to install the specific graphics drivers for this model from the HP support site, and also attempted to install drivers for this CPU from the intel support site. I got an error message both times saying that my computer does not meet the minimum requirements to install the drivers, which is odd since I ensured the drivers were for this specific device and CPU. Interestingly, all the other fn keys appear to be working fine, and the brightness controls were working fine just last night. I powered it on this morning and all brightness controls stopped working. Everything else appears to be working fine as far as I can tell. I'd greatly appreciate some help if anyone might know!

[banhien]

@natemack29 

Please download and install

   http://ftp.hp.com/pub/softpaq/sp72501-73000/sp72652.exe

Hope this helps.

Regards.

[natemack29]

Thank you for coming here to help me, I really appreciate it! I tried installing this driver you sent me and I didn't get any error message this time when I ran it, so I'm assuming it installed. I restarted the device but I'm still not able to adjust the brightness, either in the settings or with the fn buttons. 

[natemack29]

As an update, so interestingly I was able to successfully install the latest version of the Intel graphics driver after I went into Device Manager and uninstalled the existing one, rebooted, and then downloaded the latest version for this device from HP Support. I didn't get any error message, and it shows the latest driver in Device Manager. However even after installing that and rebooting, the problem remains. There is absolutely no screen setting showing anywhere within Windows, and the fn brightness keys remain dead. I even tried some PowerShell commands I read to try and just brightness on an article about this issue, and they don't work. Since I already did a PC reset which changed nothing, would it change anything to completely reinstall Windows from scratch? I would highly doubt it, but I figured I'd take a 2nd opinion before I go to that trouble. I'm starting to suspect this is a bug with Windows itself, as I can't see any logical explanation for everything else to be working perfectly, but one setting to have disappeared. 

Edit: I was able to find one slider for brightness in Windows Mobility Center, but changing it does not have any effect on the screen's brightness.