MSDN vstudio.setup:

I purchased the Visual Studio .NET 2003 evaluation product and installed and
activated it on an XP Pro SP2 machine that was fairly crufty from many
install/ uninstall cycles of various applications, services, development
tools, etc..  My goal was to try out C# and ASP.NET for web development.  
Given the state of the box, I ran into multiple problems: IIS, web server
debugging, etc..

After much frustration, I decided to wipe the hard drive, do a fresh install
of XP Pro SP2, and a fresh install of the VS .NET 2003 evaluation.  Big
mistake -- when I try to activate VS .NET over the Internet, it gives me a
dialog to the effect "this product has already been activated and can't be
activated again".  The option to telephone for activation is disabled.

If someone knows how to activate the VS .NET 2003 evaluation product a
second time, or knows for a fact that it can only be activated once, I'd like
to know.

TIA,

David