First change your runlevel. Go to /etc/inittab and change this...
# Default runlevel. (Do not set to 0 or 6)
id:4:initdefault:
Change the 5 to 3 then reboot. Then log in as root and...
Do what it tells you to do. Then change your runlevel back to 5. After that go to /etc/X11/xorg.conf and edit...
# Device configured by xf86config:
Section "Device"
Identifier "NVIDIA GeForce"
Driver "nvidia" <-----change the "nv" to "nvidia"
Option "NoLogo" "on" <----add this if you don't the nvidia logo
#VideoRam 131072
# Insert Clocks lines here if appropriate
EndSection
Reboot and your done.