-> Validating previous installation:
ERROR: File '/usr/lib/xorg/modules/extensions/libglx.so' is not a symbolic
       link.
-> done.
WARNING: Your driver installation has been altered since it was initially
         installed; this may happen, for example, if you have since installed
         the NVIDIA driver through a mechanism other than nvidia-installer
         (such as your distribution's native package management system).
         nvidia-installer will attempt to uninstall as best it can.  Please see
         the file '/var/log/nvidia-installer.log' for details.
-> Uninstalling NVIDIA Accelerated Graphics Driver for Linux-x86 (1.0-1731431
   (173.14.31)):
-> Unable to restore symbolic link /usr/lib/xorg/modules/extensions/libglx.so
   -> /etc/alternatives/libglx.so (File exists).