It sounds like your internet connection went down while in the middle of your upgrade.
Since Nautilus is unstable and typing in a file is unresponsive I think something is broken.
What is the output of:
Did you have all of the updates applied to Ubuntu Saucy Salamander 13.10 before you upgraded to 14.04?
-:-It's very important to have all updates applied to your current version of Ubuntu before you upgrade.-:-