I have installed Silverlight 2 on WinXP. I need Silverlight 2, not Silverlight 3; this is why I put 'HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Silverlight\UpdateMode = 2' into Registry - to disable automatic update. It works. Bu then I need to install Microsoft Silverlight 2 Tools for Visual Studio 2008. During install it UPDATES Silverlight 2 to Silverlight 3 (although it was Silverlight 2 Tools, not Silverlight 3 Tools)! It ignores this 'HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Silverlight\UpdateMode = 2'. Can I disable the update somehow?