Unrecognized attribute 'targetFramework' - Runtime Error

When you to try upload your site on IIS then sometimes you will get following error message:

To resolve this problem you will have to do the following configurations:

• You'll likely need to re-register ASP.Net version 4 with IIS using following command:

          C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319>aspnet_regiis -i

• To Add ASP.NET 4.0 as Application Pool on IIS 7, Windows 7

1- Go to Control Panel -> Administrative Tools -> Internet Information Services (IIS) Manager

2- Select a virtual directory or site and click on Basic Settings from the right side: :

3- A dialog box will appear on the screen, then select a Application Pool from the list.

After that click Ok.