Upgrading to Hardy borked my nvidia, as well. I ended up replacing /etc/X11/xorg.conf with xorg.conf.1, which used the generic vesa driver instead of the nvidia

Upgrading to Hardy borked my nvidia, as well. I ended up replacing /etc/X11/xorg.conf with xorg.conf.1, which used the generic vesa driver instead of the nvidia driver. (If you don't know command line, this is 'sudo /etc/X11/xorg.conf /etc/X11/xorg.conf.new-backup' followed by 'sudo /etc/X11/xorg.conf.1 /etc/X11/xorg.conf'.) After I rebooted under the vesa driver, I was able to use the Hardware Drivers tool under System/Administration to turn on the normal Hardy nvidia driver. I also recommend grabbing nvidia-settings from the repository to tweak things like multiple monitors more easily. (Once it's there, you just call 'sudo nvidia-settings'.)