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

In my case I had 2 different apps sharing the same app pool. The first one was using the .net4.5 framwork and the new one was using 2.0. When I changed the second app to it's own app pool it starting working fine with no changes to the web.config.