Locate in the list.

You can obtain the .NET Framework 3.5 SP1 through several secure methods:

The Service Pack 1 (SP1) update provides several critical improvements over the base version: Download .NET Framework 3.5 SP1

Check the box and click . Windows will automatically download and install the necessary files. Restart your computer if prompted to complete the process. Technical Features & Enhancements

Open the and type "Turn Windows features on or off".