If you already have the .NET Framework installed on a Windows 2000/XP+
system (While the framework works on other versions of Windows ASP.NET
is only supported on these) you can run the ASP.NET registration tool to
create all the correct entries.
If you're actually trying to set up on a remote machine then I recommend
that you have a look at the section in the readme that describes how to
install the bits on a remote server.