Sreen Resolution In Ubuntu8 Cant get above 640x480

[kudmus 0]

I have installed Hardy Heron on my P3 with 128MB nVidia Geforce. Although I'm enjoying every bit of the OS, I have a slight problem that is becoming very big. My screen resolution cant go above 640x480. Initially I thought it was the drivers but now I don't know the problem because my system enable the GeForce drivers automatically. It keeps telling me "monitor unknown" even when I changed from my Philips Brilliance to this Siemens 17" Has anyone encountred such a problem? How did you get around it?

[truefusion 3]

In Ubuntu's repository, there should be an Nvidia X Server Settings package which you can install (just do a search for 'nvidia' and look for it). Install it and run it with root privileges (it's going to need root privileges to save the x.org configuration file). Under "X Server Display Configuration," you should be able to pick out your resolution. After configuring things the way you want, click on "Save to X Configuration File" found under the previously mentioned category. If that doesn't change your resolution, then you may need to restart your X server (save anything you're working on before doing so). If that still doesn't help, then you may have to edit the x.org configuration file manually.