nvidia broken system on hvm

____1_________

Booting into recovery mode
Switch on your computer.
Wait until the BIOS has finished loading, or has almost finished. (During this time you will probably see a logo of your computer manufacturer.)
Quickly press and hold the Shift key, which will bring up the GNU GRUB menu. (If you see the Ubuntu logo, you've missed the point where you can enter the GRUB menu.)
Select the line which starts with "Advanced options".

Select the line ending with "(recovery mode)", probably the second line, something like:

Ubuntu GNU/Linux, with Linux 3.8.0-26-generic (recovery mode)
Press Return and your machine will begin the boot process.
After a few moments, your workstation should display a menu with a number of options. One of the options (you may need to scroll down to the bottom of the list) will be "Drop to root shell prompt". Press Return with this option highlighted.

The root partition is mounted read-only. To mount it read/write, enter the command

mount -o remount,rw /
If you have /home, /boot, /tmp, or any other mount point on a separate partition, you can mount them with the command


mount --all

https://wiki.ubuntu.com/RecoveryMode


_2___________________

Ubuntu 12.04 recovery mode root shell has no internet connection:

Plug it in to the router with an Ethernet cable and run the dhclient eth0 command.

http://askubuntu.com/questions/294199/in-the-recovery-menu-how-do-i-enable-networking-and-then-go-into-the-root-shell

__3______________

I had the same thing happen. Here is how I fixed it:

1. Switch to a terminal Ctrl+Alt+F1.
2. Login as your username.
3. Install linux headers:

   sudo apt-get install linux-headers-generic
   

4. Uninstall nvidia driver - this depends on which version you installed :

   sudo apt-get remove nvidia-current
   

   or

   sudo apt-get remove nvidia-current-updates 
   

   or

   sudo apt-get remove nvidia-experimental-304
   

5. Reinstall nvidia driver

   sudo apt-get install nvidia-current-updates
   

   When you do this, it must say something like:

   Building initial module for 3.5.0-17-generic
   Done.
   

   If it says

   Module build for the currently running kernel was
   skipped since the kernel source for this kernel
   does not seem to be installed.
   

   then the problem will not be solved. Do not believe the message. It is not asking for linux-sourceto be install, it does only want the headers but you must install the specific -generic headers for your kernel. Run:

   sudo apt-get install linux-headers-`uname -r`
   

   It will not work with just linux-headers-generic or linux-headers-3.5.0-17 (for example).
6. If it successfully installs, restart the computer :

   sudo shutdown -r now
   

This should allow the kernel module to compile and install properly. It did for me!

https://wiki.ubuntu.com/RecoveryMode