How can I add a search domain in Windows 7?

• Go to Control Panel → Network and Internet → Network and Sharing Center.
• Click on Change Adapter Settings on the left side.
• Right-click on your network adapter (normally "Local Area Connection" or "Wireless Network Connection") and select Properties.
• Select Internet Protocol version 4 (TCP/IPv4) and click on the Properties button.
• On the General tab, click on the Advanced… button.
• In the Append this DNS suffixes list, add the domains you want, like google.com.

I just tried and it worked for me. By typing "mailENTER" in Firefox, I was sent to Google Mail.