VS 2005, like its predessor, does not allow debugging for classic ASP pages, by default. This forces you to attach the ASP worker process (w3wp.exe). Follow these steps:

1. Enable ASP debugging on the server.
2. Open the Classic ASP Page in VS 2005.
3. Set breakpoint.
4. View page in browser or run without debugging.
5. Debug | Attach to Process
6. Attach the IIS ASP worker process (w3wp.exe).