How to prevent password dialog each time Outlook Corporate start?

[Anthony]

I'm using WinXP Pro SP2, Outlook 2000 Corporate/Workgroup SP3 and the outlook
is configured to use Microsoft Exchange Server service.

However, each time the Outlook start, it will prompt for username, domain
and password. There's no checkbox for me to save the password.

I've tried changing the registry using the steps in
http://support.microsoft.com/?kbid=275465.

In the Advance tab under the Exchange Server service's properties->Logon
Network Security, I've selected "NT Password Authentication". Thus, shouldn't
Outlook use my windows login credential whenever i open it? My windows login
name and password are identical to the one i used to login my mail.