I am having microsoft outlook 2003 probs. actually just e-mail provider probs.?

[muffdiver24_7_365]

my main thing is craigs list. when i click on the reply to a posting, i get outlook and when i send mail, its like its not sending. i still have all of them in the outbox and i keep getting this error message saying: task 'hotmail- sending reported error (0x800ccc33): access to the account was denied. verify that your username and password are correct. the server responded 'forbidden'.' then if i wait for just about 1 min it seems to send it but i have nothing in my sent box. it will say "task; hotmail'; sent' completed,but its all still in my outbox. it seems to just be restarting over and over and never sending anything. i have never use outlook and would really like to use my yahoo. i am using windows 7.