Well, I fixed something like this recently in 8.04
I don't know if it will work for you in 8.10

I used the search option in Synaptic and entered "envy".
Then I marked envy-core and envyng-gtk(gnome I think) for install.

It took 3 or 4 minutes. The other thing is that I had saved a
working xorg.conf from another install. Did you save your xorg.conf
from your 8.04 install which worked. My card is a geforce fx 5500
(dual screen) and I needed the working xorg.conf, not the fresh
xorg.conf that comes with a new install which isn't configured
for your card. If your card is for 3D, maybe the release notes
re: when nvidia will release a legacy driver for 8.10 apply to you.
Maybe you have an xorg.conf.bak or similar in /etc/X11, look about.