You are .NET developer and has this problem or error message while deploying your compiled apps using MS Visual Studio 2008 and try to deploy on IIS 7 or 8? Running Windows 8 Pro?
After commenting a lot in your web.config file does not help. These what you should do. It's works for me and hope it work for you as well.
I'm running Windows 8 Pro with IIS version 8.
Error message on my screen.
There is a duplicate 'system.web.extensions/scripting/scriptResourceHandler' section defined
Config File \\?\C:\inetpub\wwwroot\admin_permata\web.config
"<section name="scriptResourceHandler" type="System.Web.Configuration.ScriptingScriptResourceHandlerSection, System.Web.Extensions,......"
What should I do?
Google around and change my PC config.... it's really messy. Don't do it. You will forget what you have changed. It's just too many steps...
What I did!
In you PC control panel look for this. Turn Windows features on or off
Look for World Wide Web Services > Application Development Features
You should have this on your IIS Application Pool.
Go to your IIS Manager. Select your web site and click on "Advanced Setting"
Your app should run normally!