Error: Server Application Unavailable

I was trying to access on of the local webserver but was prompted with this error message. As usual, I'll search for the problem on Google search engine. Surprisingly, not only me who faced the problem. Even Microsoft already knew that problem might occur. As what stated on Microsoft official site,
After you install Microsoft Visual Studio .NET or the Microsoft .NET Framework on a domain controller or on a backup domain controller, if you try to run an ASP.NET application, the browser displays the following error message:
Server Application Unavailable

The web application you are attempting to access on this web server is currently unavailable.

Please hit the "Refresh" button in your web browser to retry your request.

Furthermore, the following event is logged in the system application event log:

aspnet_wp.exe could not be launched because the username and/or password supplied in the processModel section of the config file are invalid. aspnet_wp.exe could not be started. HRESULT for the failure: 80004005

This applies to Internet Information Services (IIS) version 5.0 or later.

I got to know Microsoft's help and support's solution page via Dotnet. Anyway, problem solved ;)