You need to install the .NET Framework to run many apps on Windows, such as tax filing apps and games. The .NET Framework comes from Microsoft and is updated by Windows Update.
You can also enable the .NET Framework yourself through the Control Panel in Windows. In Control Panel, choose Programs and Features, choose Turn Windows features on or off, and then select the .NET Framework check box.
The Turning Windows features on or off in Control Panel dialog will look similar to the following picture. It shows the .NET Framework 3.5, however your machine may show a different version, such as 2.0. Select the .NET Framework version you see to get your apps working.
You can learn more from this Microsoft support document on this situation.
You can also contact Microsoft for help if you cannot get the correct version of the .NET Framework installed.
This information has been provided by the .NET team.