I have an Asus laptop with Windows 8 and clicking Fn+F5 / Fn+F6 keys (for brightness) doesn't work. In fact, they work, but they can increase/decrease the brightness only one time. What I mean is that after pressing Fn+F5 once, nothing happens if I try to press Fn+F5 again, before I press Fn+F6.
This only happens after logging in. At the login screen and during Windows boot I can adjust the brightness as I want, but after login I can't.
I installed the latest ATK driver and NVIDIA graphics driver for Windows 8, and I think that my problem is related to conflict with drivers. I tried to reinstall/delete some drivers, but it didn't help.
How can I detect where is the problem?