You are told that the name and password are not valid because you have entered either a wrong name or a wrong password. If by any chance you have forgotten either of the above, just click on the "forgot password" link and give the information to verify your ownership for you to be sent your username or password.
In windows mail? If so, I haven't been able to use it since it changed from Outlook Express! I think it's a fault with the program! I used it for 10 years, same email & password! Then I got a new laptop & it had changed to Windows Mail & I can't use it anymore! No one else in my family can get in either!