Internet Information Server (IIS) does not have the necessary mappings to recognize ASP.NET file extensions and settings unless it is properly configured to work with .NET.
To check whether IIS is properly configured to interoperate with the .NET run time:
- Click Start, click Settings, click Control Panel, and double-click Administrative Tools.
- Double-click Internet Services Manager.
- On the left sidebar, expand your Web server and click to highlight Default Web Site.
- Click the Properties button in the toolbar and click the Home Directory tab.
- Click Configuration.
- Scroll through the list to find the .aspx extension. If it is listed, then your system is set up properly.
- For more information on how to associate the .NET file extensions and settings with IIS, see Microsoft Knowledge Base.