Change the Search Assistant in Internet Explorer

Start/Run/Regedit

“HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ Search”
Value Name: SearchAssistant Data Type: REG_SZ (String Value) Value Data: Search URL Create a new String value, or modify the existing value, called 'SearchAssistant' and edit the value according to the settings above.

Exit your registry, you may need to restart or log out of Windows for the change to take effect.

Note: To use the Google search assistant page enter "http://www.google.com/ie" as the URL.