I had some similar issues with am 8400GS it's not a complete howto, but it might be helpful. Anyway, these are the steps I used to get my system working,...
Open a terminal by pressing ctrl+alt+f2
Log in with linuxmce/linuxmce
Go to runlevel 1: sudo telinit 1
Run the AVWizard manually: sudo /usr/pluto/bin/AVWizard_Run.sh
AVWizard fails
Reboot: sudo reboot
Log into the terminal again
Install nvidia drivers with envy
wget http://albertomilone.com/ubuntu/nvidia/scripts/legacy/envy-0.9.10-0ubuntu10-all.deb
sudo dpkg -i envy...
sudo apt-get update
sudo apt-get install -f
Once again reboot and go to the terminal
Stop X: sudo /usr/pluto/bin/Stop_X.sh
Run AVWizard manually as described
Rebot
Easy!
Open a terminal by pressing ctrl+alt+f2
Log in with linuxmce/linuxmce
Go to runlevel 1: sudo telinit 1
Run the AVWizard manually: sudo /usr/pluto/bin/AVWizard_Run.sh
AVWizard fails
Reboot: sudo reboot
Log into the terminal again
Install nvidia drivers with envy
wget http://albertomilone.com/ubuntu/nvidia/scripts/legacy/envy-0.9.10-0ubuntu10-all.deb
sudo dpkg -i envy...
sudo apt-get update
sudo apt-get install -f
Once again reboot and go to the terminal
Stop X: sudo /usr/pluto/bin/Stop_X.sh
Run AVWizard manually as described
Rebot
Easy!
