“Unexpected Error 0×8ffe2740 Occurred” - this message appeared today on my PC when I was trying to start IIS. A while of “googling” revealed that this is rather normal behavior of the server

According to http://support.microsoft.com/kb/816944 this error occurs when some other application uses port 80 (default for a web server).

Instead of expressive error message they create KB article with explanations