Are we talking POP and SMTP?
Go to view setttings for this account, and select server settings. You should put your username in there. Username is the username you use to login to your account on the server. You also have to select the correct option in security settings, which come from your ISP. You can try "never" first, if you don't know. It will ask for your password one time, and you can select the option to let t-bird save it at that time. If it doesn't work, that's when it probably pops up a box asking for username and password. Some ISPs want just username, some want
username@your-isp.com there, so when you figure out the right combination, you can go back and edit the setting. If it doesn't work, something is wrong with the various options there. could be pop server name, port number, security settings, etc.
On the first account setttings page, you select your outgoing server on that page. You can add/edit outgoing smtp servers on the 'outgoing server pane'. If you need to use a username/password with smtp (outgoing mail) that's where you select use "user name and password" when you edit the entry for your outgoing server.
If this is for gmail, they have step-by-step instructions on their web site to set it up. gmail has some odd settings for port numbers, etc. I have a separate outgoing server set up for each of my gmail accounts, since they each have unique username/password combos. It will ask you for your password the first time you use it, and you can check the box to let t-bird save it for you if you want to. If you do it right, t-bird will ask for the security device password only once when you first start it.
Most ISPs have instructions on their web site to set up email clients since you have to know the name of the pop and smtp servers, what ports they use, if they are doing anything odd, and what security settings to use, if they have enabled any security settings on their end.
If you are adding a new email account with an existing ISP, you should be able to copy the information from the old account to the new account, but you will need to set up a separate outgoing email server and use that one with the new account if you want it to save your username/password after the first time you get logged in via the new account.
-David
