How can I get nvidia-settings to work?

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http://askubuntu.com – I have an ASUS N56VM-TB71 with a GeForce 630M graphics card. I have 12.04 and when I VGA plugged in a Dell monitor, I am able to use it. When I then use my laptop's HDMI port to plug in my second monitor, nothing happens, so I went to nvidia-settings and I got the error: You do not appear to be using the NVIDIA X Driver. Please run nvidia-xconfig as root and restart the X server. I ran this command nvidia-xconfig and rebooted but I still cannot access nvidia-settings and I keep getting that error even though my /etc/X11/xconf.org is the one that got generated by running that command. Wh (HowTos)