only terminal mode is working not Desktop mode.

I was trying to install a nvidia driver but for that I off the xserver and then installed but after that only middle half screen is coming. Then I tried to correct it but it all went wrong and now only terminal mode is coming.

Please suggest something so that I am able to correct it.

Following I am copying the output of certain commands:

1. startx *
2. output of directory /var/log/Xorg.0.log **
3. sudo service lightdm restart ***

Thanks & regards,
Ram

*** When I run this command then desktop comes back (but only in half screen ) but not able to login.

* xauth: error in locking authority file /home/ramkrishna/.Xauthority
xauth: error in locking authority file /home/ramkrishna/.Xauthority

X.Org X Server 1.11.3
Release Date: 2011-12-16
X Protocol Version 11, Revision 0
Build Operating System: Linux 2.6.42-37-generic x86_64 Ubuntu
Current Operating System: Linux ramkrishna-Dell-System-XPS-L502X 3.11.0-20-generic #35~precise1-Ubuntu SMP Fri May 2 21:32:55 UTC 2014 x86_64
Kernel command line: BOOT_IMAGE=/boot/vmlinuz-3.11.0-20-generic root=UUID=7bef1cf7-fc69-4b64-ad11-e86bd6c5221e ro quiet splash
Build Date: 16 October 2013 04:41:23PM
xorg-server 2:1.11.4-0ubuntu10.14 (For technical support please see http://www.ubuntu.com/support)
Current version of pixman: 0.30.2
 Before reporting problems, check http://wiki.x.org
 to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
 (++) from command line, (!!) notice, (II) informational,
 (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Fri May 23 19:31:13 2014
(==) Using config file: "/etc/X11/xorg.conf"
(==) Using system config directory "/usr/share/X11/xorg.conf.d"
No protocol specified
No protocol specified

** Only less than half output is pasted here
[ 162.890]
X.Org X Server 1.11.3
Release Date: 2011-12-16
[ 162.890] X Protocol Version 11, Revision 0
[ 162.890] Build Operating System: Linux 2.6.42-37-generic x86_64 Ubuntu
[ 162.890] Current Operating System: Linux ramkrishna-Dell-System-XPS-L502X 3.11.0-20-generic #35~precise1-Ubuntu SMP Fri May 2 21:32:55 UTC 2014 x86_64
[ 162.890] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-3.11.0-20-generic root=UUID=7bef1cf7-fc69-4b64-ad11-e86bd6c5221e ro quiet splash
[ 162.890] Build Date: 16 October 2013 04:41:23PM
[ 162.890] xorg-server 2:1.11.4-0ubuntu10.14 (For technical support please see http://www.ubuntu.com/support)
[ 162.890] Current version of pixman: 0.30.2
[ 162.890] Before reporting problems, check http://wiki.x.org
 to make sure that you have the latest version.
[ 162.890] Markers: (--) probed, (**) from config file, (==) default setting,
 (++) from command line, (!!) notice, (II) informational,
 (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[ 162.891] (==) Log file: "/var/log/Xorg.0.log", Time: Fri May 23 19:31:13 2014
[ 162.926] (==) Using config file: "/etc/X11/xorg.conf"
[ 162.926] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[ 162.968] (==) ServerLayout "Layout0"
[ 162.968] (**) |-->Screen "Screen0" (0)
[ 162.968] (**) | |-->Monitor "Monitor0"
[ 162.969] (**) | |-->Device "Device0"
[ 162.969] (**) |-->Input Device "Keyboard0"
[ 162.969] (**) |-->Input Device "Mouse0"
[ 162.969] (==) Automatically adding devices
[ 162.969] (==) Automatically enabling devices
[ 162.997] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist.
[ 162.997] Entry deleted from font path.
[ 162.997] (WW) The directory "/usr/share/fonts/X11/100dpi/" does not exist.
[ 162.997] Entry deleted from font path.
[ 162.997] (WW) The directory "/usr/share/fonts/X11/75dpi/" does not exist.
[ 162.997] Entry deleted from font path.
[ 162.998] (WW) The directory "/usr/share/fonts/X11/100dpi" does not exist.
[ 162.998] Entry deleted from font path.
[ 162.998] (WW) The directory "/usr/share/fonts/X11/75dpi" does not exist.
[ 162.998] Entry deleted from font path.
[ 162.998] (WW) The directory "/var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType" does not exist.
[ 162.998] Entry deleted from font path.
[ 162.998] (==) FontPath set to:
 /usr/share/fonts/X11/misc,
 /usr/share/fonts/X11/Type1,
 built-ins