Right click my computer- properties.

Select computer name tab.

Select domain option and type your domain name after it will ask user name and password.

Type server administrator user name and password.

Click ok.

Click ok.

After you can see computer name with domain name and domain name. Click apply and ok button.

Click yes.
After restart the above dialog box appears, you press ALT

Now you can log in to domain after typing user name and password by clicking log on to drop down box and selecting your domain name click ok.