If you have a POP email account e.g. with your Internet Service Provider (ISP) which is not web-based like Hotmail, Yahoo etc., you can check your messages from here, send replies and delete messages but nothing is stored on this server.
You will need your userid, password and the name of your mail server. This is the same information that you store inside your browser's email client e.g. Netscape Messenger or MS Outlook Express.

If you experience problems logging in simply Back up to this page and Login again. It is not uncommon for the POP server not to respond immediately.