click email link, TO field dont fill in

Using WindowsXP and Outlook 2003, if i click on an email link (which on my other computer fills in the To: field in the new email) does not fill in with the address on any link. I have gone into Internet Explorer, Options and changed email Program to something different then back to Outlook to no avail. What option is stopping the TO: field in the email from filling in? I am also using Norton Internet Security 2005 on both computers.