Chromium does not include Google's (Pepper) Flash Player, but there is a google-chrome.deb installer for Ubuntu, at
https://www.google.com/chrome. It should automatically add Google's package archive to your Software Sources for updating.
"seems to be a converter as well as a player"? Never heard of that, as far as I'm aware it is just the beta for the next-generation Youtube look.
You may want to take a look at this Firefox plugin:
https://addons.mozilla.org/en-US/fir...ube-all-html5/ which seems to offer a better way to enable Youtube HTML5 than merely opting in.
And here's a link to get you started on backups:
Howto: Backup and restore your system!