Try running glxinfo with and without the evn DISPLAY=:0. I would assume that the one without the display would give OpenGL version 2.1. With the display, I thing it would error out like glewinfo.

Did you make the required changes to the xorg.conf and also run the nvidia-xconfig command?

Lastly, did you the see the "Loading extension GLX..." output from the the log?
Note: all the commands with # need to be run as root or using sudo.

Try this: restart your system. Run "sudo ls". This will ask for password and get you a buffer time to run more sudo commands without entering the password each time. After sudo ls, run the "sudo /usr/bin/X :0 &amp;" command.