Password logon in Outlook

I have been using my son's computer for over a year, since he no longer uses it. I decided to change his name to mine in the start-up box and now suddenly Outlook will not let me get into my e-mail. A logon Mail Server box comes up, showing my name in the user name box and a password box with password astericks inside. When I click on OK it won't accept it. An error comes up showing user name rejected, error logging onto mail server (error 0x800CCC91). I've never had to log on to my Outlook before, it was automatic. I've tried going into all the menu options but can't locate how to eliminate the password option. I've tried changing the password but the passwords I enter are rejected. I've tried using my son's name and his prior password and that doesn't work. I don't want to use passwords at all. How can I bypass this and get my Outlook Express back to working? I've managed to turn off the password at start-up but this hasn't affected the Outlook Express at all.

 

The user name and password in Outlook are given to you by your Internet Service provider or whoever gave you the email account. You cannot just change these on your own. If you change them you cannot login to their server and retrieve your email.
Make sure you are typing your son's user name and password correctly. If you cannot get that to work at all you may have to call your ISP and explain the problem. They can change that information on their end to pertain to you if you like and you are the one paying the bill.

You can change all of these settings by going to the tools menu in Outlook and then accounts. Click on the mail tab and find your account in the window below. Click on it once to select it and then click the properties button. Under the general tab you enter your display name and email address.
Under the server tab you enter your user name and password.

 

And on the server tab, if like OE5, make sure the "server requires authentication" is unchecked.