Those questions have already been answered, and are answered again in the links provided, please do some reading for yourself, there is a lot to learn and absorb to do with multi boxing, but to answer you again:

You need to buy and own and register in your OWN name each account that you want to use for multiboxing, that means one account for each separate character.

Depending on your computer you can run more than one account on it, if you have a powerful enough computer you can run 5 accounts on it.

If you have any more questions, I suggest you post them in the New Multi-Boxers & Support forum: http://www.dual-boxing.com/forums/in...ard&boardID=11 but please do some reading first