Yes it was an upgrade, I haven't done a reinstall for many years on this machine, just upgrades. The 11.10 to 12.04 went smoothly, just reinstall of NVidia drivers to get up and running properly. I too have had problems with botched installs with Ubuntu, think it was the upgrade when they introduced Unity 11.04 possibly.
I've updated kdenlive-svn on a 32bit Ubuntu 11.10 laptop and all works ok, I'm now upgrading that to 12.04 too see if everything works after. :-)