Second acount on iceweasel

[Gary Roach <gary719_list1@verizon.net>]

I have this iceweasel account (debian machine) for technical stuff and 
another acount (thunderbird) on a win2k machine for my normal email. I 
want to transfer the win2k account to this machine. How do I do that 
without getting the two accounts intermingled.

Gary R.