First, confirm that your user ID and password are correct by double checking them. If not try logging in from another computer and see if it works since your installation may be ruined. Uninstall your Internet Explorer, start your computer again and then reinstall your Internet Explorer. Also check to ensure that all your settings are at default in the tools or internet options menu. Check your security settings to confirm that the "Check for server certificate revocation" is unchecked and the "Use SSL 2.0" and "Use SSL 3.0" is checked.