Windows 2012 Server:
1. Click Manage from the Server Manager and select Add Roles and Features to start the Add Roles and Features Wizard. Then, click on the Server Roles screen.
2. Under Web Server (IIS) role, select Web Server.
3. Under Application Development node, select ASP .NET module.
1.Click Manage from the Server Manager and select Add Roles and Features to start the Add Roles and Features Wizard. Then, click on the Features screen.
2. Under Windows Process Activation Service node, select .NET Environment feature.