ISSUE: Backlight brightness does not change.

More Detail: Brightness will not change, using both 'System Settings->Screen', or FN keys (Brightness bar shows and moves, but screen brightness does not change).

Notcied a post in this thread (http://ubuntuforums.org/showthread.php?t=1866283) about having multiple folders in Sys->Class->Backlight...

I HAVE TWO FOLDERS TOO!

'intel_backlight' and 'acpi_video0'

Using the function keys, alters the value in the acpi_video0's 'Brightness' file - But doesn't actually alter the brightness of the screen.

If I add 'backlight=vendor' in Grub, my function keys then edit the value in the 'Intel_Backlight brightness file. - But again doesnt actually change the brightness of the screen.

Computer: Fujitsu Siemans Pi2515, Intel Integrated Graphics, No hdd partition.

Already Tried:

-Editing grub to contain: acpi_osi=Linux acpi_backlight=vendor

-http://ubuntuguide.net/change-screen-brightness-with-fn-key-in-ubuntu-11-0410-10

-sudo apt-get install acpi

-$ sudo setpci -s 00:02.0 F4.B=20

-Brightness does not adjust in fallback mode either.

-Reinstalling OS, Using Linux Mint (Same problem).

-Upgrading and downgrading BIOS.

Many thanks for reading, I understand this problem may need a bit of a Linux pro to sort. If anyones up for the challenge i'll spend any amount of time being walked through this, posting results. Don't want to give up here!