help brightness decreased after updating 10.6.2

[waterplant]

hi i'm newbie in here
i've some problem with my mac
i'm using 13inch mbp with 2.26 ghz proc
when i used 10.6 everything is ok
but after updating 10.6.2 i've some trouble
my brightness decreased automatically
i don't know what really happened with my mac
i thought it wasn't wrong with my hardware
maybe in their system
i've updating with combo update
anybody who has the same problem with your mac

thanks before