By default .net framework 3.5 is not enabled on versions of Windows 10, although this is a much older version of .net it may still be a requirement for older applications and you may not want to install a newer version.
In this article we show you how to install ,net 3.5 if you need to, its an easy process
Click the Start button, type Control Panel in the search box. Then click on the Control Panel icon.
You should see something like this.
In the Control Panel window, click on Programs.
Then, you have to click on the Turn Windows features on or off option
In Windows Features dialog box, look for the option .NET Framework 3.5 (includes .NET 2.0 and 3.0).
If it is available, make sure you enable it by checking the box and then click on OK.
Windows will search for the required files.
After that, you will be displayed with two options. In that, click on Let Windows Update download the files for you.
Now, Windows will start to download the required files.
Finally, a Windows completed the required changes dialog box will be displayed and you can click the Close button
That’s it .NET Framework 3.5 (includes 2.0 and 3.0) is now installed on Windows 10.