Outlook 2003 – Cannot connect to POP3

I am running Outlook 2003 on an XP machine. My ISP for mail is Network Solutions. Out of the blue with no changes to anything, Outlook will not download mail. I tried to re-create my account, ran SCANPST, turned off Norton Internet Security 2003 nothing helped. someone suggested re-installing Outlook, but that is a last resort. Anyone with any ideas?

Thanks
Richard