Increasing brightness in HL2 EpI does not work! Please Help

I have HL2 EpI and I can not increase thr brightness in the game menu.
When I first entered the game's options menu to change the settings, the slider was at the middle and the words that appear underneath were visible.

Then I tried to increase the brightness a bit more and it went darker then it started to become brighter but at maximum brightness settings the words were not visible anymore.

After this I tried to force the brightness levels from the Catalyst Control Center, but nothing. I even tried to increase the gamma at maximum but also nothing.

I even tried older drivers and finally 2 days ago I formatted my HDD, installed the latest drivers, and still nothing. It is strange because in HL2 I could increase the brightness at my leisure. Now I am using Catalyst 6.9.

In the other games that I play like Doom3, Darkstar one, Q4, AOE3, Silent Hunter3, NFSMW I have no problem increasing the brightness from CCC
I have no idea what to do. Can anyone who had the same problem help?
Please advice

My rig is:
MOBO: Ga-K8N-PRO-sli
CPU: AMD64 3800+
RAM: 2*512mb Kingmax
HDD: Seagate 80gb sata1
CDRW: Asus
DVDRW: Lg
VGA: Sapphire AtiX1900gt
PSU: Chieftec 560W