IIS7 deployment - duplicate 'system.web.extensions/scripting/scriptResourceHandler' section

Question

On attempting to deploy a .net 3.5 website on the default app pool in IIS7 having the framework section set to 4.0, I get the following error.

There i

Answer 1

The solution for me was to change the .NET framework version in the Application Pools from v4.0 to v2.0 for the Default App Pool: