Windows XP
Normally when you attempt to open an unknown file type a popup message is shown asking whether you would like to use the online web service to find the appropriate program to open the file. This setting allows you to disable this prompt, causing the Open With dialog to display immediately.
Create a new DWORD value, or modify the existing value, called "InternetOpenWith" and set it according to the value data below.
Exit your registry; you may need to restart or log out of Windows for the change to take effect.
Note: The same change can be enforced as a system-wide policy by creating a DWORD value called "NoInternetOpenWith" at [HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\System] and setting it to "1".
Registry Settings
User Key: [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer]System Key: [HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Explorer]
Value Name: InternetOpenWith
Data Type: REG_DWORD (DWORD Value)
Value Data: (0 = hide web service, 1 = display web-service (default)
