Question fn key issue

[harshk561199]

i have an old dell latitude e6420 with an i5 second gen, and after a fresh install of windows 10 and updating it, the fn key works everywhere but the one thing i cannot do with it is controlling the brightness with fn+arrow up and down keys but when i restart the laptop it starts working i cat use fn + arrow keys to control brightness and when i shut down the pc and open it again it doesnt works the only way to get it working is to restart the laptop whats the problem with it and sorry for my bad english im a non native speaker

here's a photo of my device manager = https://ibb.co/MRXrrMT

 

[AlHuneke]

I'm not sure how to fix this, but it you right click on the Battery icon (lower left corner of the screen) and then click on Windows Mobility Center, you should be able to adjust the brightness there.

 

[harshk561199]

I'm not sure how to fix this, but it you right click on the Battery icon (lower left corner of the screen) and then click on Windows Mobility Center, you should be able to adjust the brightness there.

thanks for the reply but i already know all of these methods but the fn key system is still the fastest and best way so....