I was trying to start my IIS server recently but it could not start because of an unknown error with some number.
I've seen an entry in eventvwr.msc and searched for that in internet:
I should check whether any other process on the system uses one of http-ports (80 and 443) or better close Skype.
And really, I closed Skype and IIS worked!
My recommendation would be to check the system with TCPView from SysInternals for these ports and close the appropriate process before starting the IIS-Server.
