Upgraded to .NET Framework 4.0 - Site down

Upgraded server Framework to 4.0. Using Godaddy hosting. The website is now showing this error

500 - Internal server error. There is a problem with the resource you are looking for, and it cannot be displayed.

On searching the internet found this:

Error message when you visit a Web site that is hosted on IIS 7.0: "HTTP Error 500.0 – Internal Server Error"

The link above says:

Resolution 2 Make sure that the server that is running IIS 7.0 can access the configured root directory of the requested locat开发者_StackOverflow社区ion.

I am not sure what to do.

---

Is your Application Pool running on .NET 4.0 or .NET 2.0?

http://technet.microsoft.com/en-us/library/cc754523(WS.10).aspx

1. Open IIS Manager. For information about opening IIS Manager, see Open IIS Manager (IIS 7).
2. On the Connections pane, expand the server node and click Application Pools.
3. On the Application Pools page, select the application pool for which you want to specify a .NET Framework version, and then click Basic Settings in the Actions pane.
4. In the Edit Application Pool dialog box, in the .NET Framework version list, select the version that you want the application pool to use or select No Managed Code if the application uses only native code.
5. Click OK.

---

Moving from comment to answer so answer may be marked for future reference

Not sure if this would help, but it's an issue I ran into when upgrading to .NET 4. The person who had managed the site before me had used IIS manager to configure settings and it added references to .NET 3.5 in the web.config. Removing all references/assemblies related to 3.5 and below fixed the issue.

---

This can also happen if you are using third party controls like Telerik or if something is wrong in the web.config file. Try to remove the httpHandlers/httpModules from web.config file and if this solves the problem, you can add them one by one to check which handler/module might be causing the problem.