How to edit an already existing website.?
Hopefully whoever was editing that website before you was working with files on a computer, then uploading them to the host. If you can try and find those. If you can't, or the site was edited directly on the host, then the best thing to do is download the entire site. Edit them on a computer, then re-upload them. The reason for working this way is that a) if you screw up there's always a good copy (the one on the host you can download again). b) hosts sometimes lose files. I've know of at least three that have simply shut down or suffered a major server crash and their customers, unless they had their own copies, have lost all their files. A word of warning, most hosts only backup their own server files, any backups of the hosted sites is their customers responsibility. The things you'll need for FileZilla, or any FTP program, to work are the host's FTP address, the account username and password. They should have a help page to at least help you with the first of these.
Why does 'www.' exist if it not needed to get to a website!?
One of the guys who helped invent the internet thought it would be cool. I'm not kidding. He came out recently and said "Oh I guess that wasn't really necessary after all."
Reasons for buying an existing business?
Professionally speaking, the decision to buy a business would be after evaluating the incremental benefits of strating a new one. Incremental benefit is computed in the form of the incremental Net Present Value (NPV). If NPV of buying an existing business minus NPV of starting a new business is found possitive one will decide to buy a business. The incremental benefits would be achieved through the following ways: 1) No initial costs (it would be pretty high in most of the cases) 2) The market presents 3) Brand name 4) Less spent on advertisements ( in some cases) 5) No headache in relation to staff recrutment etc