Why is Windows 7 64 SP1 bit stuck on full brightness, FN+ keys don't work, I would like them to work. Asus N50VN. I did go to the drivers page and latest drivers did not work, I installed Nvidia from Windows Update still FN+ down keys don't work
Many notebook/laptop keyboards are designed with non-standard keyboard functionality to control things like brightness with Function (Fn) key combinations. For example, you would likely almost never see this feature on a traditional desktop keyboard, because of the vast number of keyboards and monitors of different make and model. For example, while someone may have a Samsung monitor, they may also have a Microsoft keyboard. The problem herein lies in the fact that the monitor is receiving input data from the desktop via a HDMI interface and not much else. It has been proposed that computer desktop users would have greater control over monitor functionality if a USB cable interface were added from the monitor to the desktop. This would allow, for example, the monitor to be turned off completely when the system is shutdown. However, this is widely regarded a waste of a USB port, since simply pushing a button will accomplish the same feat.
It is only in notebooks and other miniaturized systems that we see the display and the actual computer merged into one unit. Because of this, it is possible for a company like Asus to develop special tools to allow you to control your display. In fact, in your case, it is likely the only way. Adding an interface to control the display as a physical switch somewhere near the display would require additional components and miniaturized parts.
In short, you are able to execute the keyboard combinations to control your monitor precisely because: Asus has designed the entire 'banana' as it is, the keyboard, the computer, and the display.
The reason you cannot control your monitor without additional software is because Asus has not hardwired these controls into the system BIOS/CMOS. This is likely due to the restrictiveness of the modern BIOS in dealing with human interface devices like keyboards. By default, Windows controls input/output devices, and interference from a hardware call is often seen as bad design and bad practice. Windows does not support your keyboard combinations which control your display because those functions are not an absolute necessity for your system to operate. If Windows 7 was released before your laptop was created, it will not have WHQL drivers for this type of functionality.
By downloading and installing software from your manufacturer, you are unlocking the extended feature set of your keyboard as it was designed. These features are not normally found in standard keyboards and are not supposed by any known manufacturer but the one that created your Asus N50VN notebook.
A good example, to point out, would be a keyboard that can control Windows Media Player or open a program with a shortcut. These keyboards will work, but will require additional software for that extra functionality. Another example would be a gaming mouse that has certain presets or extra buttons. The mouse will work, but to unlock the special functionality, you would need software support from the manufacturer.
I hope this is a sufficient answer to your question.