Disable the Custom Search Page in Internet Explorer

Start/Run/Regedit

"HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main"
Value Name: Use Custom Search URL, Data Type: REG_DWORD (DWORD Value), Value Data: (0 = disabled, 1 = enabled). Create a new DWORD value, or modify the existing value, called 'Use Custom Search URL' and edit the value according to the settings below.

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