If the IIS web server is installed after the .NET Framework was installed, ASP.NET web pages will not work. This issue will also occur if the web server is reinstalled. The reason for this is that the ASP.NET file extensions are not being associated with the IIS mappings.
How To Fix
This can be fixed with the following procedure:
- Go to the Windows command prompt by opening the Start menu, select Run, type cmd and press OK.
- When your in the command prompt, type
Then register Aspnet_isapi.dll with the following command:
Example for Registering .NET 2.0/3.0/3.5
If you running .NET 3.0 or 3.5, you need to use the above example for .NET 2.0. This version of .NET is installed with 3.0/3.5. The newest versions do not have the aspnet_isapi.dll files in their folders. This isnâ€™t a problem because .NET 3.0/3.5 are simply v2.0 with extensions. More appropriates version numbers for the latest Frameworks should be 2.1 and 2.2 since they donâ€™t add a great deal to v2.0.