thunderbird didn't save my e-mail settings

hey guys,
i have a problem:
if i start thunderbird, i must config my account:
my username, my e-mail adress and my password
now my problem:
if i start thunderbird again, my settings are away!
at my normal computer, he just ask me for my password, but i must not enter my e-mail adress again.

i hope you understand my problem and can help me
(sorry for my english)

neamegsim