Hey there, I too use Ubuntu 5.04 Hoary with an NVIDIA video card. What you need to do, and of course I have done this and it works for me, is that you need do the following:
1.Boot Ubuntu in recovery mode and then execute the following command as a root vi /etc/apt/sources.list and edit the bottom entries which are uncommented by a #. After doing so add these 2 entries:
deb
http://archive.ubuntu.com/ubuntu hoary multiverse
deb-src
http://archive.ubuntu.com/ubuntu hoary multiverse
2.Executre apt-get update
3.apt-get install nvidia-glx
4.Again with vi edit /etc/X11/xorg.conf and change the videocard section from "nv" to "nvidia"
5.Finally just execute /etc/init.d/gdm restart
That should work, Ubuntu will install the latest nvidia drivers 71XX.
* Erase "Load dri" !!!