Microsoft .NET Framework error occurs.

Symptom:

I got the Microsoft .net Framwork error pop-up windows as below. 

Solution: 

1. Update Windows to the latest. 

   1) Click "Search" button on Windows as above.

   2) Input "Windows update" in the search box.

   3) Click "Update". 

2. Install .net framwork to the latest. 

• How to install [.NET Framework 3.5(includes .NET 2.0 and 3.0)] on WINDOWS 10.
• How to install [.NET Framework 3.5(includes .NET 2.0 and 3.0)] on WINDOWS 7