I ran into trouble trying to install Windows Sharepoint Services (WSS) when front page was enabled on the default web site. Even when I supposedly disabled Frontpage on the default web site, WSS would not install. I got around the problem by first moving the default web site to another port (say 8888). Then I’d create a new web site at port 80 and then install WSS. It installs fine. After that, you can create web sites at will and they can have either Frontpage Server Extensions or Sharepoint Extensions but NOT BOTH.