Sony Vaio display brightness problem - Windows 8

in advance, sorry if this issue has been solved on this forum, but i didn't find it.

i have sony vaio VPCS11X9E which came preinstalled with Windows 8 64bit, and everything worked fine. i was forced to reinstall Windows 8 128bit because of some old software (don't ask). as far as i can see, everything is fine except for one thing, display brightness. display is dimmed, constantly, since the login screen. i have managed to make the brightness keys to work in the sense that the brightness bar is visible and changing. however, the brightness of the screen doesn't change. i have also gone through all power and display settings, in windows and vaio control center, and have set everything on maximum, regardless of power plan etc, and tried tampering with adaptive brightness, but to no avail. right now i am a little desperate, and have no other ideas.. i'm in a bit of a hurry so i need any help or suggestion.. i hope i have provided enough information. (drivers are all updated of course).. thank you in advance.

Hi Windows,

You should take your laptop to maintenance center, I think your high-pressure plate or graphic card or screen line may be is broken. Good luck!

I have the same problem here, with the Windows 8 developer preview edition installed on one vaio notebook. Does anybody has any advice for this problem?

And, no, it isn't a problem with the hardware, because this machine has one other instance with Windows 7, using the same video card driver, and it works fine on this instance.

Thank you a lot.