i'm really glad you got yourself out of that mess
- about the "why this happened?" let's see:
you were prompted to install UP4 http://blog.linuxmint.com/?p=1949
and somehow, during the process, something broke, a package failed to install. that's why when you rebooted parts of the GUI was missing, network-manager wasn't there, FF wasn't working << because some of the pkgs and lib were updated but others that are dependents on them were still the old version.
both those 2 commands -f install
and --configure -a
will resume the upgrade process trying to install (with a force flag in the first situation) some missing pkgs.
usually this allows us to go over the oops and carry on the dist-upgrade normally to finish the rest.
it's not something new but in your situation it was made worst because 1) you did a huge update in a hurry; 2) you relied in a GUI to do it (and GUI's usually hide the most relevant information from the user)
this is not a critic (oh boy
how many times i did the same) but take it as a learning curve
- as for the last question (backups) http://clonezilla.org/
might very well be what you are looking for. it's not very intuitive at first, probably better google a couple howto's but it's powerful)