... I configured Mail for 3 separate accounts and none of it works. The only thing that happens is that a window pops up asking for one account's password and then states that it's wrong. If I go to the email server directly via the Internet it works fine. So much for Mail.
It looks like your account configuration left something to be desired, or 'something else' in Mail is on the fritz. Without prejudice, chances are it's the former. Did you check with your ISP's web site for 'how to setup' instructions? If you can't find any, we could help digging if you'd let us know the ISP(s) in question.
PS, given your successful iTunes data move I take it Target Disk Mode worked?
