For some reason, if you install IIS after you’ve installed .NET, IIS will not recognize ASP.NET pages. To fix this, go to:
Start?>Programs?>Microsoft Visual Studio.NET 2003?>Visual Studio.NET Tools?>Visual Studio .NET 2003 Command Prompt
In the Command prompt, type aspnet_regiis -i.You’re done.
Note: Visual Studio 2003 is used in this example. However, the command prompt is available in all versions.