Outlook 2000 and Exchange 5.5

I recently installed exchange 5.5 on a separate server. When I go into control panel then mail and try to add an exchange account it brings up a change password box. When I enter in my username and domain it asks for the old password and new. I do not believe I set a password. But whatever I do it states that “Your windows password could not be changes.” How can I connect to exchange?