Caution - 500 Errors with Newer PHP Builds: Trying to install PHP 7.2 on either Server 2008 SP2 or Server 2008 R2 requires the use of the VC15 Binaries and the corresponding Visual C++ Redistributable for Visual Studio 2017 (rather than Visual Studio 2015). One or both of these, that is either the PHP 7.2.x build or the C++ Redistributable for Visual Studio 2017, seem to be incompatible with IIS7 and/or those older operating systems. When testing the install of PHP 7.2.0 VC15 with the C++ Redistributable for Visual Studio 2017, the IIS 7 displays a 500 Error - Internal Server Error crashing the FastCGI Module. Also on those 2008 operating systems, you may want to avoid PHP 7.1.x as well, even though PHP 7.1.x build uses a VC14 download that corresponds to using Visual C++ Redistributable for Visual Studio 2015 (rather than 2017). 500 Errors may result using the 7.1 Binaries.
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If you have Windows Server 2008 without service pack 2 installed, then you may want to download and install Windows Server 2008 Service Pack 2. See: https://www.microsoft.com/en-us/download/confirmation.aspx?id=16468