I found a solution which worked beautifully on Windows 10:
- I first tried to find a Num Lock option in the BIOS, but found none. (ASUS G53SW)
- I then tried to reboot from the login screen with Num Lock on to see if the system would remember it, but it didn't work.
I then tried changing values in the registry:
HKEY_USERS\.DEFAULT\Control Panel\Keyboard --> "InitialKeyboardIndicators"
- Changed from default value `"214783648" to "214783650", which didn't work.
- Changed to "80000002", which didn't work.
- Changed to "2"`, which didn't work.
I reverted it to "214783650", then for some strange reason I thought that maybe Windows tries to activate it, but has trouble communicating with the keyboard controller.
- I went on my manufacturer's support site, downloaded the Intel chipset driver update utility, and the problem was solved.