If you get the following error when trying to start your IIS Website:
Unexpected error 0x8ffe2740 occurred.
Then something else has started before you and grabbed the port that the site is trying to use. For the default Website this is likely to be port 80. In my case, it's usually Skype, so I decided to sort this out once and for all. If you click Tools | Options in Skype and go to the Advanced tab and then Connection, you see the following screen:
Notice the checkbox "Use port 80 and 443 as alternatives for incoming connections"? This is actually the default, and if either of those are not available it uses the port number in "Use port X for incoming connections". So un-tick the box and click Save. Then restart Skype. You should then be able to start your Website with no issues.