Should I install original Nvidia drivers, for my Nvidia 8200. When i start installation, it asks me to close xserver. Only way to close it is use the command : "sudo service lightdm stop",because, desktop manager GDM, is not active in Ubuntu 12.02. The problem is that i do stop lightdm , this give to me a login bug also, when i run the command to stop service lightdm i get a black screen. As I do, to stop xserver, avoiding login bug?