If you have installed the .NET Framework 2.0 the following step is not necessary, ASP.NET should already be registered unless IIS was not active.
If your system’s IIS is not registered for use with ASP.NET use the Windows Command Prompt to register ASP.NET.
For applications developed with Visual Studio 2003 use the following.
From the directory C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322\ run the command aspnet_regiis –i.
For applications developed with Visual Studio 2005, 2008, and 2010 use the following if IIS is not yet registered with the .NET Framework.
From the directory C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\ run the command aspnet_regiis –i.