If you are not connected to a domain network, you can use the Network Identification Wizard to join a domain and create a local user account. If you already have a user account, you can use System Properties to join a domain. Before you join a domain, you need to connect your computer to a client/server network using a network adapter and network cable or wireless technology. After you connect a network adapter to your computer and start Windows Vista, your computer detects the network adapter and creates a local area connection. A local area connection is the only type of network connection that Windows automatically creates. Depending on your hardware setup, your Network Identification Wizard options might differ.
Join a Domain Network
Click the Start button, and then click Control Panel.
Double-click the System icon in Classic view, and then click Change settings.
Click the Computer Name tab.
Click Change.
Click the Domain option.
Type the domain name.
Click OK.
Click OK.
Join a Domain Network and Create a User Account
Click the Start button, and then click Control Panel.
Double-click the System icon in Classic view, and then click Change settings.
Click the Computer Name tab.
Click Network ID, and then click Next to continue.
Click the This computer is part of a business network option, and then click Next to continue.
Click the My company uses a network with a domain option, and then click Next to continue.