My system is a Dell Vostro 400 with the nvidia 8300GS card connected to a Dell 20" monitor on the DVI port and an ACER 22" screen on the xVGA?(15 pin blue) port.
I have run through the suggestion on searches. These steps are what allowed me to actually boot into Ubuntu without instantly freezing and scrambling my screen.
Clean install of 12.04 from CD. From login screen Ctrl+Alt+F2 to access prompt:
sudo apt-get update sudo apt-get install unity-2d sudo apt-get install nvidia-current sudo shutdown now -r
After the reboot I was able to login as myself. It's worth noting I was able to log in as a guest before the above steps, but never as myself. I have noticed that Unity seems a little sluggish but not unusable. If I start opening things and switching back and forth between programs, Unity will eventually scramble the screen graphics and become unusable or even freeze the computer. I cannot use the keyboard to get a a terminal window and so far have only been able to reboot to correct the issue.
For a reference, I have also installed Mint which I understand is basically Ubuntu with Unity removed and "Mate" (gnome) installed in it's place. Mate seems to work well, is responsive and does not hang up until I enter
Settings > Displays and basically do anything there. Regardless if I am using Unity or Mate, if I enter
Settings > Displays the result will be scrambled graphics that even repeating the original steps will not correct. I have to go through a clean install to fix it from there.
My goal is to learn and also be able to use Unity. I actually like what I have seen so far. Mate isn't bad, but it feels a little lifeless, but I would take that if it is the only way to gain stability. If the
Settings > Displays item is simply off limits and I can only use the nvidia tools to setup screens, then how do I remove the
Settings > Displays option so I don't have users trying to adjust something only to have the graphics scramble?