I did some searching but did not find anything like my problem. I was running Kubuntu 10.04 that was updated, with some third-party PPAs. Everything was working fine, but decided to upgrade to 12.04, given that support for 10.04 would not last much longer. At a terminal, I typed "sudo do-release-upgrade". It started downloading, and then installing. It said that there were errors, and now I have no networking. My version claims that it is still Lucid. However, since knetwork now no longer works (I get: "KNetworkManager cannot start because the installation is misconfigured....") , I cannot do much of anything else.
It is not easy to give any more details because I now have to type these error messages in by hand to another computer.
Since I have no connectivity, I cannot upload any logs or error reports. Neither can I reproduce the error messages that came with trying to upgrade.
I would be willing to try a fresh install, but would need some direction since I have a fully encrypted hard drive, LVM, separate home directory partition, etc.
Any help is appreciated.