Button "Fn" not working for brightness

Solution 1:

You will need a driver from Sony to get the specialty keys working. This is usually the "HKServ" driver/process (The Hotkey Service).

This may not (yet) be available from Sony as Windows 8 has not been officially released.

You can get a few versions of the HKServer application from Sony's Vaio FTP site here. Perhaps one of them will work for you.

Solution 2:

You may need to insure that the Sony software is installed. I'm not sure which one pertains to Fn, but one of them probably does.

If possible, try installing them in compatibility mode, if installing them normally doesn't fix your problem.

Does Fn work for volume?

Solution 3:

I have the same problem with Windows 8 in my Sony CS series laptop.

After installing...

1. Original - Sony® Notebook Utilities
2. System Components Sony® Firmware Extension Parser Device Driver
3. System Components Sony® Shared Library for windows 7 x64 and last update graphic driver, problem is solved.

Control settings appear to have looked like this before in Windows 7. Notice that you must first activate .Net farmework 3.5 in Windows 8.