Something similar happened to me... In my case there seems to be something amiss with the kernel modules. Try this, from the console (press Ctrl-Alt-F1 and log in), first stop the X Server and list all the loaded kernel modules related to your graphics card:


$ sudo /etc/init.d/gdm stop
$ lsmod | grep nvidia


Do you see more than one kernel module for nvidia? Do you see an i2c_core module?

Then try to remove the nvidia modules and load them manually. The first command below removes the modules, the second loads the one you need while the third restarts the graphical interface:


$ sudo rmmod nvidia
$ sudo insmod /lib/modules/`uname -r`/volatile/nvidia_legacy.ko
$ sudo /etc/init.d/gdm start


And see if you can now use nvidia-settings. All these changes are not persistent (they'll disappear after rebooting). I am still trying to make them persistent in some elegant way, in the meantime what I did is to edit the file /etc/init.d/x11-common and add the following lines at the beginning of the file (just after the set -e command):


##### SHOULDN'T BE MESSING WITH THIS
rmmod nvidia
insmod /lib/modules/2.6.24-16-generic/volatile/nvidia_legacy.ko
###### END OF MESSING


Notice that you may need to change the '2.6.24-16-generic' path to match the kernel you are using (just check the output of the uname -r command.)

Hope this helps.

Best,
AHG.

I had the same problem trying to get the drivers installed for my GeForce MX4000. Ubuntu 8.04 seemed to detect the card properly after the initial install...but enabling the restricted drivers actually lowered the resolution.I tried several methods that I found on the web and all actually forced a resolution of only 640x480.Disabling the NVIDIA drivers only allowed 800x600. I tried the EnvyNG driver app and didn't have much luck with it either. Finally gave up and set the spare PC aside for a week or two.Decided to try again this morning and dug out a spare NVIDIA card to see if a swap gave me better luck. Tried the EnvyNG app again before swapping...3 times...didn't want to take. Finally on the 3rd reboot, the login screen came up so big I couldn't see the login box...logged in blind and Voila...resolution choices galore.So you might have some luck with EnvyNG like I did. It's part of Ubuntu's "universe" repository.The developer's web page is @ www.albertomilone.com

I had a very similar problem with my Nvidia GeForce 2 MX 440 on Ubuntu 8.04.  With the nvidia driver, the screen would flash a few times over a 10 second period, and then the screen would go blank.  When I tried using the generic or "nv" drivers, I couldn't set the screen resolution over 800x600.  I tried the rmmod/insmod commands above as well as many other things.  What finally resolved it for me was putting the refresh rates of my monitor in xorg.conf.  I added the following to the Monitor section:<code>Horizsync 30.0 - 65.0Vertsync 30.0 - 90.0</code>Then after restarting gdm I was able to change the screen resolution to as high as I wanted.  I still can't use Nvidia's driver though.