How do you transfer all those emails to another account? I'm not talking about just forwarding new emails, I mean also all those other emails in the inbox.

If you create another Gmail account, you can request mail from another account. It will transfer all emails for the past 30 days. This process took about four days for me, but that was like a year ago.

To archive emails to your local computer, you would enable POP download and use a client to retrieve all the messages.

EG: http://www.howtogeek.com/68863/how-t...and-docs-data/