`startx` fails. could not find module by name='nvidia_304'

I get this output:

$ startx
X.Org X Server 1.15.1
Release Date: 2014-04-13
X Protocol Version 11, Revision 0
Build Operating System: Linux 3.2.0-70-generic x86_64 Ubuntu
Current Operating System: Linux gcomputer 3.2.0-59-lowlatency #61-Ubuntu SMP PREEMPT Tue Jan 28 09:16:18 UTC 2014 x86_64
Kernel command line: root=UUID=56fc92d2-1903-4263-b88e-d09bc15ef1d3 ro quiet splash 
Build Date: 10 December 2014  06:15:52PM
xorg-server 2:1.15.1-0ubuntu2.6 (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.1.log", Time: Tue Dec 23 13:32:06 2014
(==) Using system config directory "/usr/share/X11/xorg.conf.d"
Initializing built-in extension Generic Event Extension
Initializing built-in extension SHAPE
Initializing built-in extension MIT-SHM
Initializing built-in extension XInputExtension
Initializing built-in extension XTEST
Initializing built-in extension BIG-REQUESTS
Initializing built-in extension SYNC
Initializing built-in extension XKEYBOARD
Initializing built-in extension XC-MISC
Initializing built-in extension SECURITY
Initializing built-in extension XINERAMA
Initializing built-in extension XFIXES
Initializing built-in extension RENDER
Initializing built-in extension RANDR
Initializing built-in extension COMPOSITE
Initializing built-in extension DAMAGE
Initializing built-in extension MIT-SCREEN-SAVER
Initializing built-in extension DOUBLE-BUFFER
Initializing built-in extension RECORD
Initializing built-in extension DPMS
Initializing built-in extension Present
Initializing built-in extension DRI3
Initializing built-in extension X-Resource
Initializing built-in extension XVideo
Initializing built-in extension XVideo-MotionCompensation
Initializing built-in extension SELinux
Initializing built-in extension XFree86-VidModeExtension
Initializing built-in extension XFree86-DGA
Initializing built-in extension XFree86-DRI
Initializing built-in extension DRI2
Loading extension GLX
modprobe: ERROR: ../libkmod/libkmod-module.c:809 kmod_module_insert_module() could not find module by name='nvidia_304'
modprobe: ERROR: could not insert 'nvidia_304': Function not implemented
modprobe: ERROR: ../libkmod/libkmod-module.c:809 kmod_module_insert_module() could not find module by name='nvidia_304'
modprobe: ERROR: could not insert 'nvidia_304': Function not implemented
The XKEYBOARD keymap compiler (xkbcomp) reports:
> Warning:          Type "PC_RALT_LEVEL2" has 2 levels, but <LALT> has 3 symbols
>                   Ignoring extra symbols
Errors from xkbcomp are not fatal to the X server
xinit: connection to X server lost

waiting for X server to shut down (EE) Server terminated successfully (0). Closing log file.

xinit: unexpected signal 2

Not sure what that means. nvidia-304 is installed. Although I'm not sure if that is the correct driver and/or it was correctly installed for the correct Xorg+kernel (how can I check?). I thought I had reset all settings (in /etc), however, not sure (how can I check?).

I experienced the same issue, but only with nvidia-304 drivers. The newer nvidia-346 drivers from xorg-edgers work just fine. I resolved the issue by running the following commands (in order):

1. sudo apt-get remove --purge nvidia*
2. sudo add-apt-repository ppa:xorg-edgers/ppa
3. sudo apt-get update
4. sudo apt-get install nvidia-346

After that, my machine ran with the Nvidia graphics perfectly. Hopefully it will work for you as well.

I had the same problem. The root cause turned out to be:

• breakage of Nvidia drivers after upgrade

The solution was to find all Nvidia packages and remove then.

Find:

dpkg -l | grep -i nvidia

Remove:

sudo apt-get remove --purge nvidia-*
reboot