Dell E6430 Screen Resolution 1600x900

Hi All,

I just bought a Dell Latitude E6430 with Nvidia Graphic 5200M and support HD+ screen. I have install windows 7 64 bits on it. But i found i only able to select the max resolution up to 1366x768 instead of 1600x900. I have try to uninstall the intel grahic driver and Nvidia graphic driver, enable and disable the optimus technology under bios, update bios to latest version. So far still no luck. Any help will be much appreciated. Thanks.