My screen is black when I boot on battery

[riodoro1]

You have to press ESC right when HP logo appears, and enter BIOS config, then press fn+F3 until the brightness is full, that should do it.

Also, if you don't need F keys you can use brightness/volume regulation w/o fn key, HERE is the solution.

 

[MrDragon1]

F10 is the key to get into the HP BIOS. Just turn it on and keep hitting F10 while the HP logo is on the screen and you should see a "F10: BIOS Setup" flash on the screen then drop you in.

 

[Dewitts]

Please see probook FAQ's