Step by Step procedures in Activating .net framework 3.5.

Step1:

Search for Programs and features and click on

Step 2:

You can just press windows key + r on the keyboard and type appwiz.cpl and click ok.

Step 3:

Click Turn Windows Features On or Off on the upper left corner of the page.

Step 4:

Click on the .NET Framework 3.5 and click Ok to Activate.