I was just installing some rather nice desktop environments ( Gnome, Lubuntu, Xubuntu, etc...) when I decided, you know what? Mythbuntu sounds awesome! I'll get that too. Now whenever I log on I get crash report, an internal error, system error, and update manger is telling me "Package system broken" I don't need Mythbuntu but I do enjoy it, is there a quick and easy removal, or fix?
Can you log into the system using a CLI? If so, you could remove it from there or at least see detailed information about the error which should point us in the right direction.