Join a domain

Open System in Control Panel.
On the Network Identification tab, click Properties.
Under Member of, click Domain, type the name of the domain you want to join, and then click OK.
You will be prompted to provide a user name and user password to join the computer to the domain.
Click OK to close the System Properties dialog box.
You will be prompted to restart your computer to apply your changes.

note Note

You must be logged on as an administrator to the local computer and have a valid user name and password to join the computer to a domain. If you do not know which user name and password to use, contact your network administrator.
To open a Control Panel item, click Start, point to Settings, click Control Panel, and then double-click the appropriate icon.
You can also use the Network Identification wizard to join a domain. To use the wizard, click the Network Identification tab and then click Network ID.
It is recommended that you use computer names that are 15 characters or less. If your computer has TCP/IP networking protocol installed, the computer name can be up to 63 characters long but should only contain the numbers 0-9, the letters A-Z and a-z, and hyphens. You may use other characters, but doing so may prevent other users from finding your computer on the network. If your network is using the Microsoft DNS server, you can use any characters except periods. If other networking protocols are installed without TCP/IP, the name is limited to 15 characters.
If you specify a computer name longer than 15 characters and you want longer names to be recognized by the Active Directory domain, the domain administrator must enable registration of DNS names that are 16 bytes or longer.