Final answer:
The most likely causes for Windows login failure with a correct password are that the user account is locked, the password has expired, or the computer is not connected to the internet.
Step-by-step explanation:
If a user is trying to log into Windows on her notebook computer and the correct password has been entered but authentication fails, there could be several possible issues. The suggestion that the user account is locked is a common cause; this can happen after multiple failed login attempts as a security measure.
Another possibility is that the password has expired, which means the password is no longer valid and must be reset according to the network's security policy. The scenario that the computer is not connected to the internet can also lead to login issues, especially when the user account is a domain account that requires connectivity to authenticate against a network server.