Upgrade problem from Oneiric to Precise

[Renate]

Used the Alternate CD-ROM to upgrade from 11.10 to 12.04. Because of slow Internet connection, I said that I would update later, and it should NOT use the Internet, but it just bumped out.
I then selected the option to upgrade packages from the Internet. After about 12-13 hours the upgrade succeeded, but with some functions missing, e.g. Desktop, etc. Then ran update manager to continue the partial upgrade. Now it seems that the system is ok, but after restarting crash reports are generated, saying that the package is already installed and configured. In Synaptic under 'broken' there are a number of package. I asked for re-installation, but the crash report keep coming after restarting.