copy your nvidia drivers somewhere, lets say /usr/src. Then press for example ALT+CTRL+F2. now login as root and run this command:
now enter /usr/src and run nvidia installer. after that follow instructons on screen
chmod +x NV*
oops sorry i misunderstoodm ;p
in my opinion your problem is with /etc/X11/xorg.conf
did you install that new nvidia driver on already existed driver or it was first ever nvidia installation in your OS?