1: Restart the computer and right-click as an administrator to run. Net installer.
2: Get the system super administrator privileges, and then run the installation as an administrator.
3. Enable this function in the control panel application with the following functions:
1) enter the control panel, press the windows logo key +R, enter control or click the start icon to select the control panel.
2) Click on the program
3) Click Enable windows feature.
4) Wait for the system to change the program.
If you are connected to the Internet, windows will automatically install the update. Click after Net3.5.