How to revert to original Feisty installation?
 

I installed Feisty successfully and made a mess of things since then, installing software without packages, and worse, etc. Newbies know nothing.

Is there any way I can revert my PC Linux (Version AMD64 7.04 Feisty) back to the way it was when freshly installed?

If so, how?

Best option might be to install grunty - straight over the top. I've been running the 64-bit on a quad since (final) beta.
FWIW I split the /home out to a separate partition prior to the update. The install will recognise your current user if you use the same name, and you'll never know the difference. Just a safety thing in case it really screwed up and I had to reformat the (root) partition.

It's easy to do: just restore from your backup. That's why you made those backups, eh?

(Sorry if that seems snide, but too many people neglect their backups and then ask techs to preform miracles.)