Okay.... I don't know if the problem solved but, when I uninstall ATI Catalyst completely and restart, the problem gone (using default driver).
But when I reinstall Catalyst (latest driver, 9-11_vista64_win7_64_dd_ccc_wdm_enu) and restart, it happens again.
Edit : Okay, problem solved
. I just need to restore the Catalyst to it's factory settings (Catalyst Control Center - Options - Preferences - Restore Factory Defaults).