Not sure I understand exactly, but when I got a new tablet I just went to Fluther and logged in with my same name and password. Easy as that. I use my account on my laptop most of the time, but sometimes instead of reading in bed I come to Fluther on my tablet, and there’s no problem with transition. You know your old username, and can’t you recover/reset your password on the old computer and then just bring it over? This is one reason why I don’t use the password storage function on my various computers. If I don’t use them all the time to log in, I will forget them. A little extra typing is better than getting locked out. Also I do keep some in a notebook.