At the dashboard click create an account!
Yes.
It's made by them, that's why it's linked to Microsoft :D x
No, but you can purchase an Xbox Original version, then download an update for it from Xbox Live, if you have an account.
start a new account and get a x-box live card
On you're Xbox when you start it up it will ask you to sign in. Sign in using the info you used to actually create the account.
As of February 5, 2010, Xbox Live for the original Xbox was discontinued.
No, just change the email address in your Xbox live account.
No, I do not think this is possible. Plus, I'm sure it would corrupt the data that is the original one for account b and then use account a's Xbox Live data. Not only this, I know it's impossible to have save-data and other stuff used on another account when it's account a's information.
you can play the downloaded content on another gamertag on the same console but if u put your harddrive in another xbox the original dowloaded gamertag must be signed in a to usse the content :)
The original Xbox with live isn't support anymore, so no.
Yes
It depends on what account you used to sign up with. If you signed up with the account you used before you signed up (to get achievements) the achievements will be transferred to the new live account. On the other hand, if you create a new xbox live account you will have to start from scratch.