When installing Sharepoint 3.0 Service Pack 1 onto a fresh Windows Server 2003 installation, you can sometimes fall foul of Sharepoint complaining that ASP.net 2 is not installed:
“This product requires ASP.NET v2.0″
I found the solution over at Sharepoint Blogs. Run the following command on the server:
<code> C:\Windows\Microsoft.net\Framework\v2.0.50727\Aspnet_regiis.exe -i </code>
This will register .NET 2 with IIS and you should be able to use Sharepoint properly from that point on.