How can I improve my screen resolution?

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http://askubuntu.com – I followed the solution suggested here but making those changes in my xorg.conf file didn't help. When I restart my computer, I still have a resolution of 1280x1024 even though my native resolution is 1440x900. I have re-installed drivers a couple of times, but still nothing. Nvidia drivers version: Operating System: Linux-x86 NVIDIA Driver Version: 304.64 Server Version Number: 11.0 Screens: 1 Ubuntu 12.10 (32bit) (HowTos)