I've never seen or heard of any email address that didn't require a password to access it. If there were no password, anyone could check your email and read it from any computer so long as they had your email address. It's true that you might not have had to type one in every time to read your mail and get to your inbox, but that doesnt mean one does not exist, when this email account was created whenever that was, it did have a password set up as well, if you do not know it, you would have to get it from whomever you got the email from in the first place. here are outlook instructions from talktalk's website for outlook:
# Open Microsoft Outlook and click Next.
# You will be asked if you want to upgrade from a previous or older email package, such as Outlook Express. Unless you are upgrading, select Do Not Upgrade and click Next.
# Select Yes and click Next again.
# Tick the box labelled Manually configure server settings or additional server types and click Next.
# Select Internet E-mail and click Next.
# Enter your name and your TalkTalk email address in the first two boxes.
# Select POP3 from the Account Type drop-down list.
# Enter mail.talktalk.net in the Incoming mail server box.
# Enter smtp.talktalk.net in the Outgoing mail server (SMTP) box.
# Enter your TalkTalk email address in the User Name box and enter your password in the Password box.
# Click Next and then click Finish.
notice the next to last step advised you to put in your email address and password.
that shows us that talktalk does use them. likely you will have to call them. here is a link to where i found the setup info on their website.
http://www.talktalk.co.uk/help/questions/TEC_01_18