Windows 7: Windows Live Mail Password problem

Hi
Having a problem with Windows Live Mail.

When I try to retrieve mail I am asked for user name and password. When I OK this I am told that the details are incorrect and the following message appears...
Unable to send or receive messages for the mail.btinternet.com account. An incorrect password was entered. The next time you send or receive messages, you'll be asked to enter your user name and password for this account.

Server Error: 0x800CCC90
Server Response: -ERR [AUTH] Error logging in. Please visit http://mail.yahoo.com
Server: 'mail.btinternet.com'
Windows Live Mail Error ID: 0x800CCC92
Protocol: POP3
Port: 110
Secure(SSL): No

I know the log in details and password are correct as I am able to retreive emails sometimes but not all the time and details have not changed for six months or so.....
Also I am still able to retrieve emails via the yahoo site.

Anyone able to help as it driving me mad but I like the Windows Live and dont really want to bin it

If this problem has just started, it may be due to the mail server. It has happened to me. I would wait at least 24 hours before trying to find a solution.