de Executando o Windows 7 em grupos e domínios :
Windows 7 supports fast user switching in domain, homegroup, and workgroup configurations. When a user is logged on to a computer running Windows 7, you can use fast user switching to allow another user to log on without requiring the current user to log off.
To switch users, press Ctrl+Alt+Del, and then click the Switch User button. In a workgroup, the Log On screen is displayed as at startup. In a domain, a screen appears with the message "Press Ctrl+Alt+Del To Log On," and you must press Ctrl+Alt+Del again to display the Log On screen.
Lembre-se de digitar o nome da máquina ao alterar para o login local do domínio.