Problem after installing new driver

I have installed nvidia driver 346.72 on ubuntu 14.04 64 bits with CTRL ALT F1 …
after installation I type sudo nvidia-xconfig :

Using X configuration file: “/etc/X11/xorg.conf”. Backed up file ‘/etc/X11/xorg.conf’ as ‘/etc/X11/xorg.conf.backup’ New X configuration file written to ‘/etc/X11/xorg.conf’

Please I am waiting for answers

It would help if you would tell us what your problem is.