A colleague of mine encountered an interesting dilemma today.  All of the sudden, and seemingly out of the blue, Visual Studio .NET 2003 was reporting the following error: “...Web server is not running ASP.NET 1.1” when we've been developing applications using ASP.NET daily.  Now before we go blaming Microsoft for writing crappy software, let's take a look at the situation and try to fix it.

We did a bit of research online and the most prevalent remedy was to run aspnet_regiis -i.  In my experience you'll never really need to run that unless you install IIS after having installed Visual Studio .NET.  So we backtracked to what had changed recently.

It turns out that he had installed Skype this morning.  Everything was working great this morning, but once he rebooted, VS.NET could no longer interact with IIS.  As is so happens, Skype will steal port 80 before IIS has a chance to grab the port for its own uses.  You can, however, open Skype's options dialog and disable it from doing that.

I wonder why Skype decided to use port 80?  Perhaps it should check whether something already uses port 80 (like IIS) before auto-selecting that option...?