After Upgrading to 12.04 I can't get to the login screen

I cannot go pass the black screen and the following shows up on my screen after upgrading and rebooting with the Ubuntu update manager from 11.10 to 12.04:

ata_id [27]: HDIO_GET_IDENTITY failed for '/dev/sdb/': Invalid argument

*stopping save kernel messages

Setting up X font server socket directory /tmp/.font-unix...done.

Starting X font server:xfs.

Rather than invoking init scripts through /etc/init.d, use the service(8) utility, e.g. service S25 bluetooth start inid: Unkown job: S25 bluetooth

Since the script you are attempting to invoke has been converted to an upstart job, you may also use the start(8) utility, e.g. start S25bluetooth

*PulseAudio configured for per-user sessions

Saned disabled; edit /etc/default/saned

*Checking battery state... [OK]

After this nothing happens anymore.

I even tried booting from different linux versions and also from recovery mode. I've tried repairing the packages and even updating the grub loader.

*I have Ubuntu in an external hard drive but there were never any problems with booting before the upgrade.

*Also, it seems to be something to do with invoking init scripts rather than other problems. (If u think it isn't, still do try to help me solve the problem.)

Please help!

Solution 1:

Press CTRL+ALT+F1 and reinstall your graphic card drivers from the command line.

If you're using NVidia, it's most likely sudo apt-get purge nvidia-current and sudo apt-get install nvidia-current.
After that, run sudo reboot.

Solution 2:

You could try booting from Grub with the option:

xforcevesa

This should boot ubuntu in failsafe graphics mode. If you have a proprietary driver you can then fix it under additional drivers. If this isn't the case, you could try reinstalling xorg and its drivers:

sudo apt-get remove --purge xserver-xorg
sudo apt-get install xserver-xorg
sudo dpkg-reconfigure xserver-xorg

Solution 3:

It does look like a video driver issue that is causing plymouth and lightdm to fail to start. However, I think you'll find the machine has booted and is operational, albeit in text-only mode - try switching to the first console by holding down the CONTROL, ALT and F1 keys. Hopefully, you'll find a login screen to allow you to access the system.

Also, try booting by removing "splash" and "quiet" from the kernel command line by editing the grub menu entry. This may give more information. I would also recommend looking at /var/log/Xorg.0.log and the log files in /var/log/lightdm/ and /var/log/syslog which may give an indication as to what is going on.