Recently I installed Adobe Media Player and after that my IIS stopped working. I suspect that Adobe Media Player has hijacked the IIS default port 80.
The error I get is typical when there is a port conflict. The "Unexpected Error 0x8ffe2740 Occurred" message.
In order to test the possibility I changed the Default Web Site listening port from 80 to 81 and immediately I could start IIS.
If I want to keep Adobe Media Player which I like, I should configure it to use a different port as I want my IIS continue with what it was originally configured for.