Yes, you can. Simply remove the hard drive then insert your new one. Unless your Xbox LIVE account is on the old hard drive, then it will not affect your Xbox LIVE experience. If your account is on the old hard drive, you can move it by selecting it inside of your Storage settings, then hitting Move. After that, just choose your new hard drive and the transfer will begin.
no
there is alreay one built in
yes any size will work
Sure do what u want
no u cant
You don't. Welcome to Microsoft.
Different tvs and different accounts
No as long as you have a good Internet connection you can connect to xbox live
Yes if you have a storage device, i.e a Memory Card or Hardrive.
NO its not your hardrive still works but not the console itself
yes
Yes