During upgrading from 11.10 to 12.04 the computer crashed. Now I cannot start the computer in a normal way anymore. I get a 'Unix-like screen' where I can type commands, but I have no idea what to do. I have a CD-ROM with version 11.10 but that does not start either and I have no idea how to access the CD-drive.
something wrong happened while upgrading? connection lost? powered off?
you may try this to re-upgrade, first checking /etc/apt/source.list, and ensure that all all "deb","deb-src" lines reference to "precise" (if not, replace "oneiric"[11.10 codename] to "precise"[12.04 codename] with the vi)
Then execute the following command,
At last, execute
Hope this helps and good luck
Other (most simple) way is to insert the CD with Ubuntu 12.04, and during installation choose option to upgrade. There is quite a big chance that it will repair Your installation. Regards
From what you say you might have all the necessary packages downloaded and to hand, just their proper installation has failed.
Let's try the non-destructive bit first.
Immediately after the BIOS post hit the shift key. You should receive a grub prompt, listing the boot options. Select the one containing the term recovery Mode.
Hopefully after some text has scrolled by you will see a panel. Select the one dpkg (fix broken packages). Once the system has gone through the process (if you have a number of broken installs this might take some time. Then select resume normal boot.
You might just be lucky.