Install Optional .NET Framework 3.5 SP1
Installing .NET Framework 3.5 SP1 is optional when installing the Caching Service on Windows Vista or Windows Server 2008. .NET Framework 3.5 SP1 is recommended for the Caching Service to enable scripting using PowerShell V2.
To install .NET Framework 3.5 SP1
Go to the .NET Framework 3.5 SP1 download site (https://go.microsoft.com/fwlink/?LinkID=136345).
Review the information on the Web page, and then click Download.
Click Run.
Follow the instructions in the .NET Framework 3.5 SP1 Installation Wizard.
When installation is complete, click Finish.