Open the Server Manager application.
Access the Manage menu and click on Add roles and features.
On the Server Roles screen, expand the entry named: Web Server IIS.
Access the Application development menu and select the option named: ASP.NET
Keep in mind that you need to select the latest version available of ASP.NET.
Click on the Next button.
On the following screen, click on the Add features button.
On the Features screen, click on the Next button.
On the Summary screen, click on the Install button.
Congratulations! You have finished the ASPX installation on IIS.