http://blogs.msdn.com/knom/archive/2007/05/02/problems-with-visual-studio-2005-sp1-on-windows-2003-server.aspxLately I tried to install VS 2005 Service Pack 1 on a Windows 2003 Server via Windows Update. Unfortunately I ran into an error: Installation failed - 0x64C After searching several forum threads I found out the simple solution for the problem - insertingenCommunityServer 2.1 SP1 (Build: 61025.2)http://blogs.msdn.com/knom/archive/2007/05/02/problems-with-visual-studio-2005-sp1-on-windows-2003-server.aspx#2378393Wed, 02 May 2007 21:28:04 GMT91d46819-8472-40ad-a661-2c78acb4018c:2378393Gerard van der Land<p>I don't know if it is directly related to your issues, but there is a hotfix KB925336 (<a rel="nofollow" target="_new" href="http://support.microsoft.com/kb/925336">http://support.microsoft.com/kb/925336</a>) now for a known issue that affects installation of VS SP1 on Windows Server 2003.</p> <p>See: <a rel="nofollow" target="_new" href="http://blogs.msdn.com/heaths/archive/2007/04/24/hotfix-published-for-kb925336.aspx">http://blogs.msdn.com/heaths/archive/2007/04/24/hotfix-published-for-kb925336.aspx</a> </p> <p>A better option is slipstreaming SP1 in to an administrative image. Installation of the slipstreamed SP1 including first uninstalling the RTM, is a lot faster than applying SP1.</p> <p>See: <a rel="nofollow" target="_new" href="http://blogs.msdn.com/heaths/archive/2006/12/16/slipstreaming-visual-studio-2005-service-pack-1.aspx">http://blogs.msdn.com/heaths/archive/2006/12/16/slipstreaming-visual-studio-2005-service-pack-1.aspx</a></p>