Enable the .NET Framework 3.5 in Control Panel
You can enable the .NET Framework 3.5 yourself through Control Panel.
Step 1: Ensure you are connected to Internet. Log on to Control Panel.
Press the Windows key Windows logo on your keyboard, type Windows Features, and press Enter. This brings up the Turn Windows features on or off dialog box. Alternately, open Control Panel, click on the Programs items, and then click on “Turn Windows features on or off” under Programs and Features.
Select the .NET Framework 3.5 (includes .NET 2.0 and 3.0) check box, press OK, and reboot your computer if prompted.
You do not need to select the child items for Windows Communication Foundation (WCF) HTTP activation unless you are a developer who requires WCF script and handler mapping functionality.
Step 4: Restart your Computer.